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

cities/alexandria.md

@@ -4,18 +4,18 @@
 # Alexandria
 
 ## Overview
-Alexandria was founded by Alexander the Great in 331 BCE on the Mediterranean coast of Egypt. It became the intellectual capital of the Hellenistic world, home to the Great Library and the Pharos Lighthouse.
+Alexandria was founded by Alexander the Great in 331 BCE on the Mediterranean coast of Egypt. It became the intellectual capital of the Hellenistic world, home to the Great Library and the Pharos Lighthouse. @t[=331 BCE]
 
 ## Key Facts
 - Location: Mediterranean coast of Egypt, western Nile Delta
-- Founded: 331 BCE by Alexander the Great
-- Capital of: Ptolemaic Egypt (305–30 BCE)
+- Founded: 331 BCE by Alexander the Great @t[=331 BCE]
+- Capital of: Ptolemaic Egypt (305–30 BCE) @t[305 BCE..30 BCE]
 - Peak population: ~500,000–1,000,000 (largest city in the ancient world for centuries)
 
 ## Major Features
 - Great Library of Alexandria: Largest library of the ancient world, ~400,000–700,000 scrolls [^1]
 - Mouseion (Museum): Research institution attached to the Library
-- Pharos Lighthouse: One of the Seven Wonders, ~100–130 m tall, built ~280 BCE [^2]
+- Pharos Lighthouse: One of the Seven Wonders, ~100–130 m tall, built ~280 BCE @t[~280 BCE] [^2]
 - Serapeum: Temple of Serapis, housed part of the Library's collection
 
 ## Intellectual Legacy

cities/athens.md

@@ -8,22 +8,22 @@ Athens was the leading city-state of ancient Greece, birthplace of democracy, an
 
 ## Key Facts
 - Location: Attica, Greece
-- Period of prominence: ~508–322 BCE (democratic period)
-- Population: ~250,000–300,000 (including slaves and metics) at peak ~430 BCE
+- Period of prominence: ~508–322 BCE (democratic period) @t[508 BCE..322 BCE]
+- Population: ~250,000–300,000 (including slaves and metics) at peak ~430 BCE @t[~430 BCE]
 - Key sites: Acropolis, Agora, Pnyx, Kerameikos
 
 ## Major Monuments
-- Parthenon: Temple of Athena, built 447–432 BCE under Pericles [^1]
+- Parthenon: Temple of Athena, built 447–432 BCE under Pericles @t[447 BCE..432 BCE] [^1]
 - Erechtheion: Temple with the Caryatid porch
 - Temple of Hephaestus: Best-preserved Greek temple
 - Theatre of Dionysus: Birthplace of Greek drama
 - Stoa of Attalos: Reconstructed in the Agora
 
 ## Historical Significance
-- Birthplace of Athenian democracy (~508 BCE, Cleisthenes' reforms)
+- Birthplace of Athenian democracy (~508 BCE, Cleisthenes' reforms) @t[~508 BCE]
 - Center of philosophy: Socrates, Plato's Academy, Aristotle's Lyceum
 - Led the Delian League against Persia
-- Defeated by Sparta in the Peloponnesian War (404 BCE) [^2]
+- Defeated by Sparta in the Peloponnesian War (404 BCE) @t[=404 BCE] [^2]
 
 ---
 [^1]: Hurwit, J. *The Athenian Acropolis* (Cambridge, 1999)

cities/babylon.md

@@ -8,12 +8,12 @@ Babylon was one of the most important cities of the ancient world, located on th
 
 ## Key Facts
 - Location: Central Mesopotamia, ~85 km south of modern Baghdad, Iraq
-- Period of prominence: ~1894 BCE – 539 BCE
+- Period of prominence: ~1894 BCE – 539 BCE @t[1894 BCE..539 BCE]
 - Modern site: Hillah, Babil Governorate, Iraq
 - UNESCO World Heritage Site since 2019
 
 ## Major Features
-- Ishtar Gate: Glazed brick gate decorated with dragons and bulls, built under Nebuchadnezzar II (~575 BCE) [^1]
+- Ishtar Gate: Glazed brick gate decorated with dragons and bulls, built under Nebuchadnezzar II (~575 BCE) @t[~575 BCE] [^1]
 - Processional Way: Ceremonial avenue leading to the Esagila temple
 - Etemenanki: Ziggurat dedicated to Marduk, possibly the inspiration for the Tower of Babel
 - Hanging Gardens: One of the Seven Wonders (existence and location debated) [^2]

cities/pompeii.md

@@ -15,7 +15,7 @@ Pompeii was a Roman city near modern Naples, Italy, buried by the eruption of Mo
 
 ## Major Features
 - Forum: Central public square with temples, basilica, and markets
-- Amphitheatre: Oldest surviving Roman amphitheatre (~70 BCE)
+- Amphitheatre: Oldest surviving Roman amphitheatre (~70 BCE) @t[~70 BCE]
 - Villa of the Mysteries: Frescoes depicting Dionysiac initiation rites [^1]
 - Thermopolia: Fast-food counters (over 80 found)
 - Plaster casts of victims: Created by Giuseppe Fiorelli's technique (1863)

cities/rome.md

@@ -8,7 +8,7 @@ Rome, the "Eternal City," was the capital of the Roman Republic and Empire, grow
 
 ## Key Facts
 - Location: Central Italy, on the Tiber River
-- Traditional founding: 753 BCE (Romulus and Remus legend)
+- Traditional founding: 753 BCE (Romulus and Remus legend) @t[=753 BCE]
 - Peak population: ~1 million by the 2nd century CE
 - Key hills: Palatine, Capitoline, Aventine, and four others ("Seven Hills")
 
@@ -21,7 +21,7 @@ Rome, the "Eternal City," was the capital of the Roman Republic and Empire, grow
 - Aqueducts: 11 aqueducts supplied ~1 million cubic meters of water daily
 
 ## Historical Significance
-- Capital of a republic (509–27 BCE) and empire (27 BCE–476 CE)
+- Capital of a republic (509–27 BCE) and empire (27 BCE–476 CE) @t[509 BCE..27 BCE]
 - Center of Roman law, engineering, and administration
 - Sacked by Visigoths (410 CE) and Vandals (455 CE) @t[=410]
 - Fall of the Western Empire: 476 CE @t[=476] [^2]

cities/troy.md

@@ -4,22 +4,22 @@
 # Troy
 
 ## Overview
-Troy (ancient Ilion/Ilium) was a Bronze Age city in northwestern Anatolia, famous as the setting of Homer's *Iliad*. The archaeological site at Hisarlik reveals multiple occupation layers spanning ~3000 BCE to the Roman period.
+Troy (ancient Ilion/Ilium) was a Bronze Age city in northwestern Anatolia, famous as the setting of Homer's *Iliad*. The archaeological site at Hisarlik reveals multiple occupation layers spanning ~3000 BCE to the Roman period. @t[~3000 BCE]
 
 ## Key Facts
 - Location: Hisarlik, Çanakkale Province, Turkey
-- Period: ~3000 BCE – Roman era
+- Period: ~3000 BCE – Roman era @t[=000 BCE]
 - Excavated by: Heinrich Schliemann (1870s), Wilhelm Dörpfeld, Carl Blegen, Manfred Korfmann
 - UNESCO World Heritage Site since 1998
 
 ## Archaeological Layers
-- Troy I–V (~3000–1750 BCE): Early Bronze Age settlements
-- Troy VI (~1750–1300 BCE): Major fortified city, likely the Homeric Troy [^1]
-- Troy VIIa (~1300–1180 BCE): Destroyed by fire; candidate for the Trojan War destruction
+- Troy I–V (~3000–1750 BCE): Early Bronze Age settlements @t[3000 BCE..1750 BCE]
+- Troy VI (~1750–1300 BCE): Major fortified city, likely the Homeric Troy @t[1750 BCE..1300 BCE] [^1]
+- Troy VIIa (~1300–1180 BCE): Destroyed by fire; candidate for the Trojan War destruction @t[1300 BCE..1180 BCE]
 - Troy VIII–IX: Greek and Roman Ilion
 
 ## The Trojan War
-- Traditionally dated ~1184 BCE (Eratosthenes' calculation)
+- Traditionally dated ~1184 BCE (Eratosthenes' calculation) @t[~1184 BCE]
 - Homer's *Iliad* describes a Greek siege of Troy over the abduction of Helen
 - Historical basis debated; may reflect Bronze Age conflicts between Mycenaeans and Anatolian powers [^2]
 

cities/ur.md

@@ -8,17 +8,17 @@ Ur was one of the most important Sumerian city-states, located in southern Mesop
 
 ## Key Facts
 - Location: Tell el-Muqayyar, Dhi Qar Province, Iraq
-- Period: ~3800 BCE – ~500 BCE
+- Period: ~3800 BCE – ~500 BCE @t[3800 BCE..500 BCE]
 - Excavated by: Leonard Woolley (1922–1934)
 
 ## Major Discoveries
-- Royal Tombs of Ur (~2600–2400 BCE): Elaborate burials with gold, lapis lazuli, and human sacrifices [^1]
+- Royal Tombs of Ur (~2600–2400 BCE): Elaborate burials with gold, lapis lazuli, and human sacrifices @t[2600 BCE..2400 BCE] [^1]
 - Standard of Ur: Mosaic box depicting war and peace scenes
-- Great Ziggurat of Ur: Built by Ur-Nammu (~2100 BCE), partially restored
+- Great Ziggurat of Ur: Built by Ur-Nammu (~2100 BCE), partially restored @t[~2100 BCE]
 - Ram in a Thicket: Gold and lapis lazuli figurine (now in British Museum and Penn Museum)
 
 ## Historical Significance
-- Third Dynasty of Ur (~2112–2004 BCE): Last Sumerian dynasty, produced the Code of Ur-Nammu
+- Third Dynasty of Ur (~2112–2004 BCE): Last Sumerian dynasty, produced the Code of Ur-Nammu @t[2112 BCE..2004 BCE]
 - Major trading port connected to the Persian Gulf
 - Traditionally identified as "Ur of the Chaldees" (Genesis 11:31) [^2]