Add 1525 checkpoint: Ilkhanate golden age, Anatolia conquest, Reformation

Ilkhanate at zenith:
- Conquers Anatolia (~1500-1520), gains Mediterranean coast
- Vassalizes Khoqand (Central Asia) — controls Silk Road from Anatolia to Song border
- Sassanid + Ottoman + maritime trade + industrialization combined
- World's second industrial power, may approach Song's level by V3 era

Byzantine reduced to city-state (Constantinople + Thrace only)
Mediterranean triple division: Aragon (west), Italian cities (center), Ilkhanate (east)
Great Khanate loses Byzantine proxy, core shrinking

Reformation erupts (~1510s-1520s):
- Germany as epicenter, Hussite ideas + printing press reach critical mass
- English separatism + Reformation beginning to merge in Plantagenet France

Columbus aftermath: Portuguese colonizing Caribbean, Aztec/Inca contact imminent
Song: Eastern Han stability, innovation stagnating

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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@@ -1187,16 +1187,95 @@ These will cause future fragmentation episodes (Three Kingdoms / Five Dynasties
 
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-## Open Questions (Post-1500 Chronological Development)
-
-1. **Song**: When does the next fragmentation episode happen? Does it reach V3 era unified or divided?
-2. **Americas**: Portuguese colonization develops — New World silver/gold enters global economy?
-3. **Reformation**: Formal break — which countries go Protestant-equivalent? Religious wars?
-4. **Ilkhanate**: Full industrialization timeline? Becomes Song's peer competitor?
-5. **Great Khanate**: Continued decline — when do Poland/Northern Ulus/Byzantium break away?
-6. **English separatism**: Does England break from Plantagenet France? When?
-7. **Aragon**: Peak and decline? Or sustained great power?
-8. **India**: Timurid-Indian unification — does it succeed?
-9. **Remaining timeline to 1836**: 336 years, ~13 checkpoints at 25-year intervals
+## 1525 Checkpoint: Ilkhanate Golden Age
+
+### Ilkhanate Conquers Anatolia (~1500-1520)
+- **Motivation**: Mediterranean coastline, eliminate Byzantine/Great Khanate proxy in Levant, consolidate Syria
+- **Why now**: Ilkhanate at military/industrial peak. Byzantium weak. Great Khanate can't reinforce across thousands of km.
+- **Anatolian population**: Majority Turkic/Muslim → may welcome Islamic Ilkhanate over Orthodox Byzantine rule
+- **Crossing Caucasus to attack Great Khanate directly**: NOT worth it (mountain logistics, low reward — serfs and grassland)
+- **Result**: Anatolia falls. Syria fully consolidated. Ilkhanate gains eastern Mediterranean coast.
+
+### Ilkhanate Vassalizes Central Asia (~1510s-1520s)
+- Khoqand Khanate (Timurid remnant in Transoxiana) squeezed between Great Khanate (north) and Ilkhanate (south)
+- Chooses submission to Ilkhanate over destruction → becomes vassal
+- Ilkhanate now controls Silk Road from Anatolia through Persia to Central Asia (edge of Song's Western Protectorate)
+
+### Ilkhanate at Zenith (~1525)
+**Territory/sphere**: Persia (core) + Iraq + Khorasan + western Afghanistan + Syria + Anatolia (newly conquered) + Khoqand/Transoxiana (vassal) + Egypt (semi-autonomous) + Indian Ocean trading network (Gujarat, Malabar, East Africa, Indonesian outposts, Japan direct route)
+- Essentially: **Sassanid Persia + Ottoman Empire + maritime trade network + early industrialization**
+- The largest Islamic power in this world's history
+- World's second industrial power (after Song, but Song is stagnating while Ilkhanate is growing)
+- **May be approaching Song's level by V3 era (1836)**
+
+### Byzantine Empire: Reduced to City-State
+- Lost Anatolia → retains only Constantinople + Thrace (small European strip)
+- **NOT destroyed**: Constantinople's walls + strait geography still formidable. Ilkhanate doesn't need to take it.
+- Transforms into **neutral trade city-state** (similar to Venice or Singapore): too weak for politics, too valuable to destroy
+- Black Sea → Mediterranean trade node still functions
+- Great Khanate nominally still suzerain but cannot protect or control it
+- Constantinople Orthodoxy survives as religious center (Patriarchate) but the political empire is dead
+
+### Mediterranean Power Triangle (~1525)
+| Zone | Controller |
+|---|---|
+| Western Mediterranean | Aragon (Barcelona → Naples) |
+| Central Mediterranean | Italian city-states (Venice, Genoa, Florence) — buffer zone |
+| Eastern Mediterranean | Ilkhanate (Anatolian coast, Syria, Egypt's Red Sea) |
+- Venice in extremely delicate position: middleman between Aragon and Ilkhanate, both of whom want to bypass it
+- Genoa may align with one side or the other for survival
+
+### Great Khanate: Losing Its Proxies
+- **Byzantium effectively lost** as a Mediterranean/Balkan proxy
+- Balkans: now managed only through weakening Bulgar Khanate vassal → less control, more chaos
+- Northern Ulus: practically independent
+- Poland: expanding self-governance
+- Core shrinking to: Volga capital → Ukraine → Hungary → Kazakhstan steppe
+- **Agricultural serfdom economy** cannot compete with industrializing neighbors (Ilkhanate, Germany)
+
+### Song (~1525): Eastern Han Stability
+- Military junta government stable but uninspiring
+- Industrial production continues, innovation still slow
+- Western Protectorate: fully independent warlord state
+- SE Asian colonies: patchwork of direct control, autonomous governors, independent Chinese polities
+- North-South divide reduced but structural problems (landlords, military politics) persist
+- Australia: small but growing coastal Chinese settlements
+
+### Columbus Aftermath (~1500-1525)
+- Portuguese colonizing Caribbean islands (Hispaniola, Cuba base)
+- Gold found → investment accelerates
+- First mainland expeditions (equivalent of Cortés/Pizarro timing, ~1520s)
+- **Aztec/Inca contact imminent or just occurring**
+- New World gold/silver beginning to flow back to Portugal → economic boom
+- Castile sending own expeditions, claiming territories Portugal hasn't reached
+- Kalmar Union: Vinland (Newfoundland) settlements growing, cod fishery major industry
+
+### Reformation Erupts (~1510s-1520s)
+- 50+ years of Hussite reform ideas + printing press = critical mass reached
+- **Germany most likely epicenter**: Hanseatic merchant class receptive, political independence from Rome, printing infrastructure
+- Formal break from Papacy — German reformed church established?
+- Spreads to: Bohemia (reform movement's birthplace), possibly Burgundy, English-speaking parts of Plantagenet France
+- **Catholic powers' response**: Aragon (strongly Catholic, Mediterranean), Plantagenet France (Paris court may stay Catholic to differentiate from Protestant English subjects), Papal States
+- Religious divide begins reshaping European alliances
+- V3 era: Protestant-equivalent vs Catholic as major political fault line in Europe
+
+### Plantagenet France: English Problem Grows
+- English-speaking island population increasingly alienated from French-speaking Paris court
+- Reform/Protestant ideas find receptive audience in England (anti-Rome = anti-Paris proxy)
+- **English separatism + Reformation may merge**: religious independence as vehicle for political independence
+- Not yet a revolution but the ingredients are assembling
+
+---
+
+## Open Questions (Post-1525 Chronological Development)
+
+1. **Song**: When does the next crisis hit? Does it reach 1836 unified?
+2. **Americas**: Aztec/Inca conquest? Portuguese vs Castile colonial rivalry? New World silver impact?
+3. **Reformation wars**: Religious conflict in Europe — who fights whom?
+4. **English independence**: When does England break from Plantagenet France?
+5. **Ilkhanate**: Continues growing or overextended? Egypt finally breaks away?
+6. **Great Khanate**: When does it finally collapse or reform?
+7. **India**: Timurid-Indian unification progress?
+8. **Remaining to 1836**: 311 years, ~12 checkpoints
 7. **Timurid-India**: Does unification succeed?
 8. **1836 world**: We're now 360 years from V3 start — what's the trajectory?