How did a few hundred Spanish soldiers topple two empires? – Si Sheppard

Summary · 4 min read instead of 1 h 37 m

Si Sheppard is a military historian whom Dwarkesh Patel introduces as a professor. The episode draws on his account of the Spanish conquests of the Aztec and Inca empires and of European expansion more broadly.

Sheppard argues the conquistadors won because steel weapons and horses combined with diplomacy: over 99 percent of the force that took Tenochtitlan was made up of native allies who resented Aztec rule. Seizing the Aztec and Inca rulers worked because those societies were hierarchical. The natives did adapt, but they had little time, and disease would likely have broken the empires anyway. Sheppard says Spain gained little lasting benefit from American silver, which brought inflation and stalled its development. He puts the conquistadors' motives down to ambition and greed, with religion as justification, and says rivalries between native peoples blocked a united front.

Minute by minute

1. 1:20

   Cortés exploits resentment of Aztec rule. Sheppard traces the conquest to Europe's push into the Atlantic and Columbus's 1492 voyage. In 1518 Cortés turned Governor Velázquez's warrant into an expedition inland. Sheppard says Cortés saw early that subject peoples resented imperial rule. The Totonacs joined him, and the Tlaxcalans did too after fighting him to a standstill.

2. 6:05

   Steel and horses mattered more than guns. Sheppard says guns counted for little once natives got over the shock, given slow reloading. Steel helmets and Toledo thrusting swords beat wood, stone and obsidian weapons. Horses were decisive inland, since the Aztecs had no beast of burden and only the turkey and chihuahua as domestic animals. Cavalry broke formations and allowed a fast retreat.

3. 9:49

   Seizing Moctezuma delivered the empire. At Tenochtitlan, Cortés used an attack on Spaniards on the coast as a pretext to take Moctezuma II into custody, and the emperor complied. Sheppard thinks letting Cortés in was Moctezuma's best option. He says the mistake was staying within reach, because without the emperor Cortés would have had very limited options.

4. 14:35

   Diplomacy rescued Cortés after defeat. Cortés won over the force Velázquez sent to arrest him. Alvarado's massacre at a festival turned the city against the Spanish, and Cortés escaped on La Noche Triste. Sheppard says the Tlaxcalans took him back on their own terms. The final force was about one-half of one percent Spanish, and it carried prefabricated boats over the mountains.

5. 23:18

   Pizarro repeated the playbook at Cajamarca. Sheppard says Pizarro arrived with 168 men during an Inca civil war, and Atahualpa had just won it. Atahualpa ignored his envoy's advice to burn the Spaniards in their sleep. In a narrow courtyard Pizarro attacked with artillery, muskets and horses and captured him. The host puts the dead near 10,000, and Sheppard says the only Spanish injury was Pizarro's hand.

6. 31:47

   Natives adapted, but the timeline was too short. Sheppard says loose Mesoamerican formations suited cavalry, unlike Swiss pikes. Aztecs fought from rooftops and in confined city terrain, and broke dikes to flood a city. The Inca flooded a river, mounted swords on poles and used bolas, and Manco Inca learned to ride. Sheppard says the learning curve was too steep for the time they had.

7. 35:33

   Cusco showed the limits of Inca numbers. Sheppard says the conquest could have failed if Cortés had died early, or if Atahualpa had kept envoys at a distance. The Inca won in mountain passes with boulders, but lost on open ground near Lima. Spanish cavalry in Cusco's plazas and growing numbers of native allies saved the besieged. Sheppard notes that only a small elite spoke the imperial languages.

8. 41:10

   Disease would have undone the empires. Sheppard says Eurasia's domesticated animals bred contagious diseases that never arose in the New World, so the Americas had no immunity to smallpox. He thinks even short-term native victories would have been undone by demographic crisis and by subject peoples breaking away. He adds that Europeans would eventually have pushed inland from the coast.

9. 45:28

   Hierarchy made the empires fragile. Responding to the host's Comanche example, Sheppard says taking the Aztec or Inca ruler destabilized the whole system. Dispersed peoples like the Maya had to be reduced city by city, until the end of the 17th century. He says the Tarascans' copper-tipped arrows beat the Aztecs, and that Aztecs and Incas shared no knowledge.

10. 56:12

    American silver did not enrich Spain. The host argues the conquest created no net wealth, and silver shipped to China made up for Ming currency problems. Sheppard says silver funded Charles V and Philip II's wars. He says it also brought inflation and falling real wages, and Spain never built capital markets as the Netherlands and England did. Potosí completed the pieces of globalization.

11. 1:07:43

    Culture limited Aztec and Inca tactics. The host lists mistakes: the Aztecs trying to capture Cortés for sacrifice, marked generals, and Cusco's rebels resting at night. Sheppard says Aztec warfare rewarded captives with status and was tied to religion, which could not change in the time available. He adds that the Inca besiegers drifted home to harvest.

12. 1:14:12

    Conquistadors sought status and gold. Sheppard says many conquistadors came from poor Extremadura with only fighting skills, and the Caribbean conquests looked easy. Religion gave them legitimacy, and he thinks their horror at Aztec human sacrifice was genuine. Gold remained the real aim. He says the humanitarian motive was at best window dressing, and the host calls the conquest genocidal.

13. 1:23:13

    Native rivalries blocked a united front. The host asks why the natives could not exploit Spanish divisions. Sheppard says the Spanish rivalries were within one system and they would have united against a common threat. Cuitláhuac sent emissaries to the Tlaxcalans and Tarascans, who refused. Playing European powers against each other was impossible while the Spanish were the only players.

14. 1:26:20

    Company governance helped Britain in India. Sheppard says the Mughal Empire would have disintegrated without Europeans, and the Royal Navy let Britain project power. The host argues the East India Company could replace leaders, unlike hereditary monarchies. Sheppard agrees, citing the tax revenue of Bengal, and calls the conquistadors freebooters in a capitalist system.

Published Oct 1, 2026.