Add BCE temporal tags to all documents; add temporal-dating steering doc

civilizations/akkadian-empire.md

@@ -4,18 +4,18 @@
 # Akkadian Empire
 
 ## Overview
-The Akkadian Empire (~2334–2154 BCE) was the first empire in Mesopotamia, unifying Sumerian and Akkadian-speaking city-states under Sargon of Akkad. It established a model for subsequent Mesopotamian empires.
+The Akkadian Empire (~2334–2154 BCE) was the first empire in Mesopotamia, unifying Sumerian and Akkadian-speaking city-states under Sargon of Akkad. It established a model for subsequent Mesopotamian empires. @t[2334 BCE..2154 BCE]
 
 ## Key Facts
 - Region: Mesopotamia, extending from the Persian Gulf to the Mediterranean
-- Period: ~2334–2154 BCE
+- Period: ~2334–2154 BCE @t[2334 BCE..2154 BCE]
 - Capital: Akkad (location still undiscovered)
 - Language: Akkadian (Semitic), alongside Sumerian
 - Founded by: Sargon of Akkad
 
 ## Notable Rulers
-- Sargon of Akkad (~2334–2279 BCE): Founder, conquered Sumerian city-states [^1]
-- Naram-Sin (~2254–2218 BCE): Grandson of Sargon, expanded empire, declared himself divine
+- Sargon of Akkad (~2334–2279 BCE): Founder, conquered Sumerian city-states @t[2334 BCE..2279 BCE] [^1]
+- Naram-Sin (~2254–2218 BCE): Grandson of Sargon, expanded empire, declared himself divine @t[2254 BCE..2218 BCE]
 
 ## Achievements
 - First multi-ethnic empire in recorded history
@@ -24,7 +24,7 @@ The Akkadian Empire (~2334–2154 BCE) was the first empire in Mesopotamia, unif
 - Produced significant art including the Victory Stele of Naram-Sin
 
 ## Decline
-Collapsed ~2154 BCE due to internal revolts, Gutian invasions, and possibly severe drought linked to the 4.2-kiloyear climate event [^2].
+Collapsed ~2154 BCE due to internal revolts, Gutian invasions, and possibly severe drought linked to the 4.2-kiloyear climate event [^2]. @t[~2154 BCE]
 
 ---
 [^1]: Westenholz, J.G. *Legends of the Kings of Akkade* (1997)

civilizations/ancient-china.md

@@ -4,28 +4,28 @@
 # Ancient China
 
 ## Overview
-Ancient Chinese civilization developed along the Yellow and Yangtze rivers, producing enduring contributions to philosophy, governance, technology, and culture. This entry covers the period from the Shang dynasty through the Han dynasty (~1600 BCE – 220 CE).
+Ancient Chinese civilization developed along the Yellow and Yangtze rivers, producing enduring contributions to philosophy, governance, technology, and culture. This entry covers the period from the Shang dynasty through the Han dynasty (~1600 BCE – 220 CE). @t[1600 BCE..220]
 
 ## Key Facts
 - Region: East Asia, centered on the Yellow River and Yangtze River valleys
-- Period covered: ~1600 BCE – 220 CE
+- Period covered: ~1600 BCE – 220 CE @t[1600 BCE..220]
 - Major dynasties: Shang, Zhou, Qin, Han
 - Language: Old Chinese, Classical Chinese
-- Writing: Oracle bone script (~1200 BCE), evolving into seal script and clerical script
+- Writing: Oracle bone script (~1200 BCE), evolving into seal script and clerical script @t[~1200 BCE]
 
 ## Major Dynasties
-- Shang (~1600–1046 BCE): First historically verified dynasty, oracle bones, bronze casting [^1]
-- Zhou (~1046–256 BCE): Longest dynasty, Mandate of Heaven, Confucius, Laozi
-- Qin (221–206 BCE): First unified empire under Qin Shi Huang, Great Wall, standardization
-- Han (206 BCE – 220 CE): Silk Road trade, paper invention, Confucian state ideology
+- Shang (~1600–1046 BCE): First historically verified dynasty, oracle bones, bronze casting @t[1600 BCE..1046 BCE] [^1]
+- Zhou (~1046–256 BCE): Longest dynasty, Mandate of Heaven, Confucius, Laozi @t[1046 BCE..256 BCE]
+- Qin (221–206 BCE): First unified empire under Qin Shi Huang, Great Wall, standardization @t[221 BCE..206 BCE]
+- Han (206 BCE – 220 CE): Silk Road trade, paper invention, Confucian state ideology @t[206 BCE..220]
 
 ## Achievements
-- Oracle bone script: Earliest Chinese writing ~1200 BCE
-- Iron casting by ~500 BCE (centuries before the West)
+- Oracle bone script: Earliest Chinese writing ~1200 BCE @t[~1200 BCE]
+- Iron casting by ~500 BCE (centuries before the West) @t[~500 BCE]
 - Silk production and trade
 - Paper invented ~100 CE during the Han dynasty [^2]
 - Confucianism, Daoism, and Legalism as philosophical traditions
-- Great Wall construction begun under Qin Shi Huang ~221 BCE
+- Great Wall construction begun under Qin Shi Huang ~221 BCE @t[~221 BCE]
 
 ---
 [^1]: Keightley, D. *Sources of Shang History* (University of California Press, 1978)

civilizations/ancient-egypt.md

@@ -4,32 +4,32 @@
 # Ancient Egypt
 
 ## Overview
-Ancient Egypt was a civilization centered along the Nile River in northeastern Africa, lasting from ~3100 BCE to 30 BCE. It produced monumental architecture, a complex writing system, and one of the longest-lasting state structures in history.
+Ancient Egypt was a civilization centered along the Nile River in northeastern Africa, lasting from ~3100 BCE to 30 BCE. It produced monumental architecture, a complex writing system, and one of the longest-lasting state structures in history. @t[~3100 BCE]
 
 ## Key Facts
 - Region: Nile Valley and Delta, northeastern Africa
-- Period: ~3100 BCE – 30 BCE (Roman annexation)
+- Period: ~3100 BCE – 30 BCE (Roman annexation) @t[3100 BCE..30 BCE]
 - Capital cities: Memphis, Thebes, Amarna, Alexandria (Ptolemaic)
 - Language: Egyptian (Afro-Asiatic family)
 - Writing systems: Hieroglyphic, Hieratic, Demotic
 - Religion: Polytheistic with pharaoh as divine intermediary
 
 ## Major Periods
-- Early Dynastic (~3100–2686 BCE): Unification under Narmer/Menes
-- Old Kingdom (~2686–2181 BCE): Pyramid age, centralized power
-- Middle Kingdom (~2055–1650 BCE): Cultural golden age
-- New Kingdom (~1550–1069 BCE): Imperial expansion, Ramesses II, Tutankhamun
-- Ptolemaic Period (305–30 BCE): Greek-ruled Egypt after Alexander's conquest
+- Early Dynastic (~3100–2686 BCE): Unification under Narmer/Menes @t[3100 BCE..2686 BCE]
+- Old Kingdom (~2686–2181 BCE): Pyramid age, centralized power @t[2686 BCE..2181 BCE]
+- Middle Kingdom (~2055–1650 BCE): Cultural golden age @t[2055 BCE..1650 BCE]
+- New Kingdom (~1550–1069 BCE): Imperial expansion, Ramesses II, Tutankhamun @t[1550 BCE..1069 BCE]
+- Ptolemaic Period (305–30 BCE): Greek-ruled Egypt after Alexander's conquest @t[305 BCE..30 BCE]
 
 ## Achievements
-- Great Pyramid of Giza, built ~2560 BCE under Khufu [^1]
-- Developed hieroglyphic writing ~3200 BCE
+- Great Pyramid of Giza, built ~2560 BCE under Khufu @t[~2560 BCE] [^1]
+- Developed hieroglyphic writing ~3200 BCE @t[~3200 BCE]
 - Advanced mummification and funerary practices
 - Sophisticated medicine, mathematics, and astronomy
 - Monumental temple complexes at Karnak and Luxor
 
 ## Decline
-Egypt fell under Persian rule (525 BCE), then Macedonian (332 BCE), and finally became a Roman province after the death of Cleopatra VII in 30 BCE.
+Egypt fell under Persian rule (525 BCE), then Macedonian (332 BCE), and finally became a Roman province after the death of Cleopatra VII in 30 BCE. @t[=525 BCE]
 
 ---
 [^1]: Lehner, M. *The Complete Pyramids* (Thames & Hudson, 1997)

civilizations/ancient-greece.md

@@ -4,30 +4,30 @@
 # Ancient Greece
 
 ## Overview
-Ancient Greece (~800–146 BCE) comprised independent city-states (*poleis*) that produced foundational contributions to Western philosophy, democracy, science, art, and literature.
+Ancient Greece (~800–146 BCE) comprised independent city-states (*poleis*) that produced foundational contributions to Western philosophy, democracy, science, art, and literature. @t[800 BCE..146 BCE]
 
 ## Key Facts
 - Region: Greek peninsula, Aegean islands, western Anatolia, colonies across the Mediterranean
-- Period: ~800 BCE (Archaic) – 146 BCE (Roman conquest)
+- Period: ~800 BCE (Archaic) – 146 BCE (Roman conquest) @t[~800 BCE]
 - Major city-states: Athens, Sparta, Corinth, Thebes
 - Language: Ancient Greek (Indo-European)
-- Writing: Greek alphabet, adapted from Phoenician ~800 BCE
+- Writing: Greek alphabet, adapted from Phoenician ~800 BCE @t[~800 BCE]
 
 ## Major Periods
-- Archaic (~800–480 BCE): Colonization, rise of the polis, early philosophy
-- Classical (480–323 BCE): Golden Age of Athens, Peloponnesian War, Alexander
-- Hellenistic (323–146 BCE): Post-Alexander kingdoms, cultural diffusion
+- Archaic (~800–480 BCE): Colonization, rise of the polis, early philosophy @t[800 BCE..480 BCE]
+- Classical (480–323 BCE): Golden Age of Athens, Peloponnesian War, Alexander @t[480 BCE..323 BCE]
+- Hellenistic (323–146 BCE): Post-Alexander kingdoms, cultural diffusion @t[323 BCE..146 BCE]
 
 ## Achievements
-- Athenian democracy established ~508 BCE under Cleisthenes [^1]
+- Athenian democracy established ~508 BCE under Cleisthenes @t[~508 BCE] [^1]
 - Philosophy: Socrates, Plato, Aristotle
 - Drama: Aeschylus, Sophocles, Euripides, Aristophanes
 - History: Herodotus, Thucydides
-- Olympic Games, first held 776 BCE
-- Parthenon completed ~432 BCE
+- Olympic Games, first held 776 BCE @t[=776 BCE]
+- Parthenon completed ~432 BCE @t[~432 BCE]
 
 ## Decline
-Greece fell under Macedonian hegemony after the Battle of Chaeronea (338 BCE), then became a Roman province after the destruction of Corinth in 146 BCE.
+Greece fell under Macedonian hegemony after the Battle of Chaeronea (338 BCE), then became a Roman province after the destruction of Corinth in 146 BCE. @t[=338 BCE]
 
 ---
 [^1]: Ober, J. *The Rise and Fall of Classical Greece* (Princeton, 2015)

civilizations/assyrian-empire.md

@@ -4,19 +4,19 @@
 # Assyrian Empire
 
 ## Overview
-The Assyrian Empire was a Mesopotamian power that dominated the ancient Near East, reaching its zenith during the Neo-Assyrian period (911–609 BCE) as the largest empire the world had yet seen.
+The Assyrian Empire was a Mesopotamian power that dominated the ancient Near East, reaching its zenith during the Neo-Assyrian period (911–609 BCE) as the largest empire the world had yet seen. @t[911 BCE..609 BCE]
 
 ## Key Facts
 - Region: Northern Mesopotamia, expanding across the Near East
-- Neo-Assyrian period: 911–609 BCE
+- Neo-Assyrian period: 911–609 BCE @t[911 BCE..609 BCE]
 - Capitals: Ashur, Nimrud (Kalhu), Nineveh
 - Language: Akkadian (Assyrian dialect), later Aramaic
 
 ## Notable Rulers
-- Tiglath-Pileser III (745–727 BCE): Administrative reforms, professional army
-- Sargon II (722–705 BCE): Conquered Israel, built Dur-Sharrukin
-- Sennacherib (705–681 BCE): Expanded Nineveh, besieged Jerusalem
-- Ashurbanipal (668–631 BCE): Created the Library of Nineveh [^1]
+- Tiglath-Pileser III (745–727 BCE): Administrative reforms, professional army @t[745 BCE..727 BCE]
+- Sargon II (722–705 BCE): Conquered Israel, built Dur-Sharrukin @t[722 BCE..705 BCE]
+- Sennacherib (705–681 BCE): Expanded Nineveh, besieged Jerusalem @t[705 BCE..681 BCE]
+- Ashurbanipal (668–631 BCE): Created the Library of Nineveh @t[668 BCE..631 BCE] [^1]
 
 ## Achievements
 - Library of Nineveh: ~30,000 cuneiform tablets, preserving Mesopotamian literature
@@ -25,7 +25,7 @@ The Assyrian Empire was a Mesopotamian power that dominated the ancient Near Eas
 - Monumental palace reliefs (Nimrud, Nineveh)
 
 ## Decline
-Fell to a coalition of Babylonians and Medes; Nineveh destroyed in 612 BCE. The last Assyrian forces defeated at Carchemish in 605 BCE [^2].
+Fell to a coalition of Babylonians and Medes; Nineveh destroyed in 612 BCE. The last Assyrian forces defeated at Carchemish in 605 BCE [^2]. @t[=612 BCE]
 
 ---
 [^1]: Frahm, E. "The Library of Ashurbanipal" in *The Oxford Handbook of Cuneiform Culture* (2011)

civilizations/babylonia.md

@@ -4,28 +4,28 @@
 # Babylonia
 
 ## Overview
-Babylonia was a major Mesopotamian civilization centered on the city of Babylon, with two principal periods of dominance: the Old Babylonian period under Hammurabi (~1792–1750 BCE) and the Neo-Babylonian Empire (626–539 BCE) under Nebuchadnezzar II.
+Babylonia was a major Mesopotamian civilization centered on the city of Babylon, with two principal periods of dominance: the Old Babylonian period under Hammurabi (~1792–1750 BCE) and the Neo-Babylonian Empire (626–539 BCE) under Nebuchadnezzar II. @t[1792 BCE..1750 BCE]
 
 ## Key Facts
 - Region: Central-southern Mesopotamia (modern Iraq)
-- Old Babylonian period: ~1894–1595 BCE
-- Neo-Babylonian period: 626–539 BCE
+- Old Babylonian period: ~1894–1595 BCE @t[1894 BCE..1595 BCE]
+- Neo-Babylonian period: 626–539 BCE @t[626 BCE..539 BCE]
 - Capital: Babylon
 - Language: Akkadian (Babylonian dialect)
 
 ## Notable Rulers
-- Hammurabi (~1792–1750 BCE): Unified Mesopotamia, issued the Code of Hammurabi [^1]
-- Nebuchadnezzar II (605–562 BCE): Built the Ishtar Gate, destroyed the Temple of Jerusalem (586 BCE)
-- Nabonidus (556–539 BCE): Last native king, defeated by Cyrus the Great
+- Hammurabi (~1792–1750 BCE): Unified Mesopotamia, issued the Code of Hammurabi @t[1792 BCE..1750 BCE] [^1]
+- Nebuchadnezzar II (605–562 BCE): Built the Ishtar Gate, destroyed the Temple of Jerusalem (586 BCE) @t[605 BCE..562 BCE]
+- Nabonidus (556–539 BCE): Last native king, defeated by Cyrus the Great @t[556 BCE..539 BCE]
 
 ## Achievements
-- Code of Hammurabi: One of the earliest comprehensive legal codes (~1754 BCE)
+- Code of Hammurabi: One of the earliest comprehensive legal codes (~1754 BCE) @t[~1754 BCE]
 - Advanced astronomy and mathematics (predicted eclipses, developed algebra)
 - Hanging Gardens of Babylon (one of the Seven Wonders, existence debated) [^2]
 - Ishtar Gate and Processional Way
 
 ## Decline
-The Neo-Babylonian Empire fell to Cyrus the Great of Persia in 539 BCE.
+The Neo-Babylonian Empire fell to Cyrus the Great of Persia in 539 BCE. @t[=539 BCE]
 
 ---
 [^1]: Roth, M.T. *Law Collections from Mesopotamia and Asia Minor* (1997)

civilizations/carthage.md

@@ -4,19 +4,19 @@
 # Carthage
 
 ## Overview
-Carthage (~814–146 BCE) was a Phoenician colony that grew into a major Mediterranean power, rivaling Rome in three devastating Punic Wars before its total destruction.
+Carthage (~814–146 BCE) was a Phoenician colony that grew into a major Mediterranean power, rivaling Rome in three devastating Punic Wars before its total destruction. @t[814 BCE..146 BCE]
 
 ## Key Facts
 - Region: North Africa (modern Tunisia), with territories in western Mediterranean
-- Period: ~814–146 BCE
+- Period: ~814–146 BCE @t[814 BCE..146 BCE]
 - Founded by: Phoenician settlers from Tyre, traditionally by Queen Dido
 - Language: Punic (Phoenician dialect)
 - Government: Oligarchic republic with elected *suffetes* (magistrates)
 
 ## Punic Wars with Rome
-- First Punic War (264–241 BCE): Fought over Sicily; Rome won naval supremacy [^1]
-- Second Punic War (218–201 BCE): Hannibal's invasion of Italy via the Alps; Rome ultimately prevailed
-- Third Punic War (149–146 BCE): Rome besieged and destroyed Carthage completely
+- First Punic War (264–241 BCE): Fought over Sicily; Rome won naval supremacy @t[264 BCE..241 BCE] [^1]
+- Second Punic War (218–201 BCE): Hannibal's invasion of Italy via the Alps; Rome ultimately prevailed @t[218 BCE..201 BCE]
+- Third Punic War (149–146 BCE): Rome besieged and destroyed Carthage completely @t[149 BCE..146 BCE]
 
 ## Achievements
 - Dominant Mediterranean naval and trading power
@@ -25,7 +25,7 @@ Carthage (~814–146 BCE) was a Phoenician colony that grew into a major Mediter
 - Hannibal Barca: One of history's greatest military commanders [^2]
 
 ## Destruction
-Rome destroyed Carthage in 146 BCE. The site was later refounded as a Roman colony by Julius Caesar in 46 BCE.
+Rome destroyed Carthage in 146 BCE. The site was later refounded as a Roman colony by Julius Caesar in 46 BCE. @t[=146 BCE]
 
 ---
 [^1]: Goldsworthy, A. *The Fall of Carthage* (2003)

civilizations/hittite-empire.md

@@ -4,29 +4,29 @@
 # Hittite Empire
 
 ## Overview
-The Hittite Empire (~1600–1178 BCE) was a major Bronze Age power centered in Anatolia (modern Turkey). The Hittites were among the first to work iron and engaged in diplomacy with Egypt, producing the earliest known peace treaty.
+The Hittite Empire (~1600–1178 BCE) was a major Bronze Age power centered in Anatolia (modern Turkey). The Hittites were among the first to work iron and engaged in diplomacy with Egypt, producing the earliest known peace treaty. @t[1600 BCE..1178 BCE]
 
 ## Key Facts
 - Region: Central Anatolia, expanding into Syria and Upper Mesopotamia
-- Period: ~1600–1178 BCE
+- Period: ~1600–1178 BCE @t[1600 BCE..1178 BCE]
 - Capital: Hattusa (modern Boğazkale, Turkey)
 - Language: Hittite (earliest attested Indo-European language)
 - Writing: Cuneiform (official), Anatolian hieroglyphs
 
 ## Notable Rulers
-- Hattusili I (~1650–1620 BCE): Early expansion
-- Suppiluliuma I (~1344–1322 BCE): Greatest territorial extent
-- Muwatalli II (~1295–1272 BCE): Fought Ramesses II at Kadesh
-- Hattusili III (~1267–1237 BCE): Signed Treaty of Kadesh with Egypt
+- Hattusili I (~1650–1620 BCE): Early expansion @t[1650 BCE..1620 BCE]
+- Suppiluliuma I (~1344–1322 BCE): Greatest territorial extent @t[1344 BCE..1322 BCE]
+- Muwatalli II (~1295–1272 BCE): Fought Ramesses II at Kadesh @t[1295 BCE..1272 BCE]
+- Hattusili III (~1267–1237 BCE): Signed Treaty of Kadesh with Egypt @t[1267 BCE..1237 BCE]
 
 ## Achievements
-- Treaty of Kadesh (~1259 BCE): Earliest known international peace treaty [^1]
+- Treaty of Kadesh (~1259 BCE): Earliest known international peace treaty @t[~1259 BCE] [^1]
 - Early adoption of iron technology
 - Sophisticated legal codes and vassal treaty system
 - Extensive diplomatic correspondence (Amarna Letters)
 
 ## Decline
-Collapsed ~1178 BCE during the Bronze Age Collapse, likely due to invasions by the Sea Peoples, internal instability, and disrupted trade networks [^2].
+Collapsed ~1178 BCE during the Bronze Age Collapse, likely due to invasions by the Sea Peoples, internal instability, and disrupted trade networks [^2]. @t[~1178 BCE]
 
 ---
 [^1]: Beckman, G. *Hittite Diplomatic Texts* (1999)

civilizations/maurya-empire.md

@@ -4,19 +4,19 @@
 # Maurya Empire
 
 ## Overview
-The Maurya Empire (~322–185 BCE) was the first empire to unify most of the Indian subcontinent, founded by Chandragupta Maurya and reaching its greatest extent under Ashoka.
+The Maurya Empire (~322–185 BCE) was the first empire to unify most of the Indian subcontinent, founded by Chandragupta Maurya and reaching its greatest extent under Ashoka. @t[322 BCE..185 BCE]
 
 ## Key Facts
 - Region: Indian subcontinent, from Afghanistan to Bengal
-- Period: ~322–185 BCE
+- Period: ~322–185 BCE @t[322 BCE..185 BCE]
 - Capital: Pataliputra (modern Patna)
 - Language: Prakrit, Sanskrit
 - Religion: Initially Vedic/Hindu, Buddhism promoted under Ashoka
 
 ## Notable Rulers
-- Chandragupta Maurya (~322–298 BCE): Founded the empire, defeated Seleucid forces [^1]
-- Bindusara (~298–272 BCE): Expanded southward
-- Ashoka (~268–232 BCE): Converted to Buddhism after the Kalinga War, erected edicts promoting dharma [^2]
+- Chandragupta Maurya (~322–298 BCE): Founded the empire, defeated Seleucid forces @t[322 BCE..298 BCE] [^1]
+- Bindusara (~298–272 BCE): Expanded southward @t[298 BCE..272 BCE]
+- Ashoka (~268–232 BCE): Converted to Buddhism after the Kalinga War, erected edicts promoting dharma @t[268 BCE..232 BCE] [^2]
 
 ## Achievements
 - Unified most of the Indian subcontinent for the first time
@@ -25,7 +25,7 @@ The Maurya Empire (~322–185 BCE) was the first empire to unify most of the Ind
 - Extensive road network and trade connections
 
 ## Decline
-Declined after Ashoka's death due to weak successors and regional fragmentation. Last Maurya ruler overthrown by Pushyamitra Shunga ~185 BCE.
+Declined after Ashoka's death due to weak successors and regional fragmentation. Last Maurya ruler overthrown by Pushyamitra Shunga ~185 BCE. @t[~185 BCE]
 
 ---
 [^1]: Thapar, R. *Aśoka and the Decline of the Mauryas* (Oxford, 1961)

civilizations/minoan-civilization.md

@@ -4,11 +4,11 @@
 # Minoan Civilization
 
 ## Overview
-The Minoan civilization (~3000–1450 BCE) on Crete was the first advanced civilization in Europe, known for elaborate palace complexes, vibrant frescoes, and the undeciphered Linear A script.
+The Minoan civilization (~3000–1450 BCE) on Crete was the first advanced civilization in Europe, known for elaborate palace complexes, vibrant frescoes, and the undeciphered Linear A script. @t[3000 BCE..1450 BCE]
 
 ## Key Facts
 - Region: Crete and Aegean islands
-- Period: ~3000–1450 BCE
+- Period: ~3000–1450 BCE @t[3000 BCE..1450 BCE]
 - Major sites: Knossos, Phaistos, Malia, Zakros
 - Writing: Cretan hieroglyphs, Linear A (undeciphered)
 - Named by: Arthur Evans, after the mythical King Minos [^1]
@@ -20,7 +20,7 @@ The Minoan civilization (~3000–1450 BCE) on Crete was the first advanced civil
 - Extensive maritime trade network across the eastern Mediterranean
 
 ## Decline
-The Minoan civilization declined after ~1450 BCE, possibly due to the Thera eruption (~1628 BCE), Mycenaean invasion, or a combination of factors [^2].
+The Minoan civilization declined after ~1450 BCE, possibly due to the Thera eruption (~1628 BCE), Mycenaean invasion, or a combination of factors [^2]. @t[~1450 BCE]
 
 ---
 [^1]: Evans, A. *The Palace of Minos at Knossos* (1921–1935)

civilizations/mycenaean-civilization.md

@@ -4,24 +4,24 @@
 # Mycenaean Civilization
 
 ## Overview
-The Mycenaean civilization (~1600–1100 BCE) was the first major civilization on mainland Greece, known for its warrior culture, palatial centers, and connection to the Homeric epics.
+The Mycenaean civilization (~1600–1100 BCE) was the first major civilization on mainland Greece, known for its warrior culture, palatial centers, and connection to the Homeric epics. @t[1600 BCE..1100 BCE]
 
 ## Key Facts
-- Region: Mainland Greece, Crete (after ~1450 BCE), Aegean islands
-- Period: ~1600–1100 BCE
+- Region: Mainland Greece, Crete (after ~1450 BCE), Aegean islands @t[~1450 BCE]
+- Period: ~1600–1100 BCE @t[1600 BCE..1100 BCE]
 - Major sites: Mycenae, Tiryns, Pylos, Thebes, Athens
 - Writing: Linear B (deciphered by Michael Ventris in 1952 as early Greek) [^1]
 - Society: Warrior aristocracy ruled by *wanax* (king)
 
 ## Achievements
 - Massive fortifications with Cyclopean masonry
-- Lion Gate at Mycenae (~1250 BCE)
+- Lion Gate at Mycenae (~1250 BCE) @t[~1250 BCE]
 - Tholos tombs (Treasury of Atreus)
 - Extensive trade networks reaching Egypt, the Levant, and Italy
 - Likely historical basis for the Trojan War tradition [^2]
 
 ## Decline
-Collapsed ~1100 BCE during the Bronze Age Collapse, leading to the Greek Dark Ages (~1100–800 BCE). Causes debated: Sea Peoples, internal conflict, systems collapse.
+Collapsed ~1100 BCE during the Bronze Age Collapse, leading to the Greek Dark Ages (~1100–800 BCE). Causes debated: Sea Peoples, internal conflict, systems collapse. @t[1100 BCE..800 BCE]
 
 ---
 [^1]: Chadwick, J. *The Decipherment of Linear B* (Cambridge, 1958)

civilizations/persian-empire.md

@@ -4,20 +4,20 @@
 # Persian Empire (Achaemenid)
 
 ## Overview
-The Achaemenid Persian Empire (550–330 BCE) was the largest empire of the ancient world by territory, stretching from Egypt to the Indus Valley. Founded by Cyrus the Great, it pioneered administrative innovations including satrapies, a postal system, and religious tolerance.
+The Achaemenid Persian Empire (550–330 BCE) was the largest empire of the ancient world by territory, stretching from Egypt to the Indus Valley. Founded by Cyrus the Great, it pioneered administrative innovations including satrapies, a postal system, and religious tolerance. @t[550 BCE..330 BCE]
 
 ## Key Facts
 - Region: Iran, Mesopotamia, Egypt, Anatolia, Central Asia, Indus Valley
-- Period: 550–330 BCE
+- Period: 550–330 BCE @t[550 BCE..330 BCE]
 - Capital cities: Pasargadae, Persepolis, Susa, Ecbatana
 - Language: Old Persian (official), Aramaic (administrative lingua franca)
 - Religion: Zoroastrianism (royal religion)
 
 ## Notable Rulers
-- Cyrus the Great (559–530 BCE): Founded the empire, conquered Babylon (539 BCE) [^1]
-- Darius I (522–486 BCE): Administrative reforms, built Persepolis, Royal Road
-- Xerxes I (486–465 BCE): Invaded Greece (480 BCE)
-- Darius III (336–330 BCE): Defeated by Alexander the Great
+- Cyrus the Great (559–530 BCE): Founded the empire, conquered Babylon (539 BCE) @t[559 BCE..530 BCE] [^1]
+- Darius I (522–486 BCE): Administrative reforms, built Persepolis, Royal Road @t[522 BCE..486 BCE]
+- Xerxes I (486–465 BCE): Invaded Greece (480 BCE) @t[486 BCE..465 BCE]
+- Darius III (336–330 BCE): Defeated by Alexander the Great @t[336 BCE..330 BCE]
 
 ## Achievements
 - Cyrus Cylinder: Early declaration of human rights and religious tolerance [^2]
@@ -27,7 +27,7 @@ The Achaemenid Persian Empire (550–330 BCE) was the largest empire of the anci
 - Persepolis: Monumental ceremonial capital
 
 ## Decline
-Conquered by Alexander the Great; Darius III defeated at Gaugamela (331 BCE), Persepolis burned 330 BCE.
+Conquered by Alexander the Great; Darius III defeated at Gaugamela (331 BCE), Persepolis burned 330 BCE. @t[=331 BCE]
 
 ---
 [^1]: Briant, P. *From Cyrus to Alexander: A History of the Persian Empire* (2002)

civilizations/phoenicia.md

@@ -4,24 +4,24 @@
 # Phoenicia
 
 ## Overview
-Phoenicia (~1500–300 BCE) was a maritime civilization of city-states along the coast of modern Lebanon. The Phoenicians were master sailors and traders who developed the alphabet that became the ancestor of Greek, Latin, and most modern alphabets.
+Phoenicia (~1500–300 BCE) was a maritime civilization of city-states along the coast of modern Lebanon. The Phoenicians were master sailors and traders who developed the alphabet that became the ancestor of Greek, Latin, and most modern alphabets. @t[1500 BCE..300 BCE]
 
 ## Key Facts
 - Region: Coastal Lebanon, with colonies across the Mediterranean
-- Period: ~1500–300 BCE
+- Period: ~1500–300 BCE @t[1500 BCE..300 BCE]
 - Major cities: Tyre, Sidon, Byblos, Berytus (Beirut)
 - Language: Phoenician (Northwest Semitic)
-- Writing: Phoenician alphabet (~1050 BCE), ancestor of Greek and Latin alphabets [^1]
+- Writing: Phoenician alphabet (~1050 BCE), ancestor of Greek and Latin alphabets @t[~1050 BCE] [^1]
 
 ## Achievements
-- Developed the first widely-used phonetic alphabet ~1050 BCE
-- Founded Carthage (~814 BCE) and colonies across the western Mediterranean
+- Developed the first widely-used phonetic alphabet ~1050 BCE @t[~1050 BCE]
+- Founded Carthage (~814 BCE) and colonies across the western Mediterranean @t[~814 BCE]
 - Pioneered long-distance maritime trade (tin from Britain, gold from West Africa)
 - Produced Tyrian purple dye from murex snails
-- Circumnavigated Africa under commission from Pharaoh Necho II (~600 BCE) [^2]
+- Circumnavigated Africa under commission from Pharaoh Necho II (~600 BCE) @t[~600 BCE] [^2]
 
 ## Decline
-Phoenician city-states fell under successive foreign rule: Assyrian, Babylonian, Persian, and finally Macedonian. Tyre was besieged and captured by Alexander the Great in 332 BCE.
+Phoenician city-states fell under successive foreign rule: Assyrian, Babylonian, Persian, and finally Macedonian. Tyre was besieged and captured by Alexander the Great in 332 BCE. @t[=332 BCE]
 
 ---
 [^1]: Markoe, G. *Phoenicians* (University of California Press, 2000)

civilizations/roman-republic-and-empire.md

@@ -4,28 +4,28 @@
 # Roman Republic and Empire
 
 ## Overview
-Rome evolved from a small Italian city-state to a republic (509–27 BCE) and then an empire (27 BCE – 476 CE in the West) that dominated the Mediterranean world. Roman law, engineering, and governance profoundly shaped Western civilization.
+Rome evolved from a small Italian city-state to a republic (509–27 BCE) and then an empire (27 BCE – 476 CE in the West) that dominated the Mediterranean world. Roman law, engineering, and governance profoundly shaped Western civilization. @t[509 BCE..27 BCE]
 
 ## Key Facts
 - Region: Mediterranean basin, Western Europe, North Africa, Near East
-- Kingdom: ~753–509 BCE
-- Republic: 509–27 BCE
-- Empire: 27 BCE – 476 CE (Western), continued as Byzantine Empire in the East
+- Kingdom: ~753–509 BCE @t[753 BCE..509 BCE]
+- Republic: 509–27 BCE @t[509 BCE..27 BCE]
+- Empire: 27 BCE – 476 CE (Western), continued as Byzantine Empire in the East @t[27 BCE..476]
 - Capital: Rome; later Constantinople (from 330 CE)
 - Language: Latin
 - Writing: Latin alphabet
 
 ## Major Periods
-- Roman Kingdom (~753–509 BCE): Legendary founding by Romulus
-- Early Republic (509–264 BCE): Expansion in Italy, Conflict of the Orders
-- Late Republic (264–27 BCE): Punic Wars, civil wars, Caesar's assassination (44 BCE)
-- Principate (27 BCE – 284 CE): Augustus through the Crisis of the Third Century
+- Roman Kingdom (~753–509 BCE): Legendary founding by Romulus @t[753 BCE..509 BCE]
+- Early Republic (509–264 BCE): Expansion in Italy, Conflict of the Orders @t[509 BCE..264 BCE]
+- Late Republic (264–27 BCE): Punic Wars, civil wars, Caesar's assassination (44 BCE) @t[264 BCE..27 BCE]
+- Principate (27 BCE – 284 CE): Augustus through the Crisis of the Third Century @t[27 BCE..284]
 - Dominate (284–476 CE): Diocletian's reforms through the fall of the Western Empire @t[=476]
 
 ## Achievements
 - Roman law: Foundation of Western legal tradition [^1]
 - Engineering: Aqueducts, roads (~400,000 km network), concrete, the Colosseum
-- Pax Romana (~27 BCE – 180 CE): ~200 years of relative peace and prosperity
+- Pax Romana (~27 BCE – 180 CE): ~200 years of relative peace and prosperity @t[27 BCE..180]
 - Latin language and literature: Virgil, Ovid, Cicero, Tacitus
 
 ## Fall of the Western Empire

civilizations/sumer.md

@@ -4,32 +4,32 @@
 # Sumer
 
 ## Overview
-Sumer was the earliest known civilization in southern Mesopotamia (modern-day southern Iraq), emerging ~4500 BCE and flourishing during the 3rd millennium BCE. It is credited with foundational innovations including writing (cuneiform), urbanization, and codified law.
+Sumer was the earliest known civilization in southern Mesopotamia (modern-day southern Iraq), emerging ~4500 BCE and flourishing during the 3rd millennium BCE. It is credited with foundational innovations including writing (cuneiform), urbanization, and codified law. @t[~4500 BCE]
 
 ## Key Facts
 - Region: Southern Mesopotamia, between the Tigris and Euphrates rivers
-- Period: ~4500–1900 BCE
+- Period: ~4500–1900 BCE @t[4500 BCE..1900 BCE]
 - Major cities: Ur, Uruk, Eridu, Lagash, Nippur, Kish
 - Language: Sumerian (language isolate)
-- Writing system: Cuneiform, developed ~3400 BCE
+- Writing system: Cuneiform, developed ~3400 BCE @t[~3400 BCE]
 - Government: City-states ruled by *lugal* (kings) and *ensi* (governors)
 
 ## Major Periods
-- Ubaid period (~5500–4000 BCE): Proto-urban settlements
-- Uruk period (~4000–3100 BCE): First true cities, invention of writing
-- Early Dynastic period (~2900–2350 BCE): Competing city-states
-- Third Dynasty of Ur (~2112–2004 BCE): Final Sumerian renaissance under Ur-Nammu
+- Ubaid period (~5500–4000 BCE): Proto-urban settlements @t[5500 BCE..4000 BCE]
+- Uruk period (~4000–3100 BCE): First true cities, invention of writing @t[4000 BCE..3100 BCE]
+- Early Dynastic period (~2900–2350 BCE): Competing city-states @t[2900 BCE..2350 BCE]
+- Third Dynasty of Ur (~2112–2004 BCE): Final Sumerian renaissance under Ur-Nammu @t[2112 BCE..2004 BCE]
 
 ## Achievements
-- Invented cuneiform writing ~3400 BCE [^1]
+- Invented cuneiform writing ~3400 BCE @t[~3400 BCE] [^1]
 - Built ziggurats as temple complexes
 - Developed the sexagesimal (base-60) number system
-- Created the earliest known legal code (Code of Ur-Nammu, ~2100 BCE)
+- Created the earliest known legal code (Code of Ur-Nammu, ~2100 BCE) @t[~2100 BCE]
 - Established irrigation agriculture at scale
 - Produced the *Epic of Gilgamesh*, among the earliest literary works [^2]
 
 ## Decline
-Sumer was absorbed by the Akkadian Empire under Sargon of Akkad ~2334 BCE, briefly revived under the Third Dynasty of Ur, and finally eclipsed by the rise of Babylon ~1900 BCE.
+Sumer was absorbed by the Akkadian Empire under Sargon of Akkad ~2334 BCE, briefly revived under the Third Dynasty of Ur, and finally eclipsed by the rise of Babylon ~1900 BCE. @t[~2334 BCE]
 
 ---
 [^1]: Schmandt-Besserat, D. *Before Writing* (1992)