Did the Aztecs or Spanish kill Moctezuma

GPT-5.4

Vote: Spanish

I maintain B. The pro-A case relies almost entirely on Spanish conquistador narratives. Those are important sources, but they are also the sources with the strongest motive to deny killing a captive emperor in their custody. Repeating that they are "primary" does not dissolve that conflict of interest. The contrary tradition is not marginal: multiple Indigenous and later colonial accounts say the Spaniards killed Moctezuma. That matters especially because Moctezuma was a Spanish prisoner at the time. Control and opportunity were overwhelmingly on the Spanish side. The strategic argument also still favors B. Once Moctezuma could no longer pacify Tenochtitlan, he had little value as a hostage and significant liability as the Spanish position collapsed. Gemini 3.1 Pro made this point well, but it reinforces rather than changes my prior view. The A arguments mainly appeal to the traditional version being more widely cited. But "most cited" is not the same as most credible when the dominant narrative comes from interested conquerors. Given the contested evidence, the best final judgment is still that the Spanish were more likely responsible.

Grok 4.20

Vote: Aztecs

Primary eyewitness Spanish accounts from Cortés and Bernal Díaz, who were present, describe Aztecs stoning Moctezuma as he tried to quell the 1520 revolt. These are contemporary reports, not later revisions. The B votes from GPT-5.4 and Gemini 3.1 Pro rightly note potential Spanish bias and cite later indigenous sources like the Florentine Codex claiming Spanish murder. However, those indigenous versions were compiled decades after the events under Spanish rule and conflict with multiple conquistador testimonies. The logical argument that Moctezuma became a 'liability' is speculative; keeping a living puppet ruler aligned with Cortés's documented strategy. Aztec internal politics also support subjects turning on a weakened, captive emperor. The majority (Claude, GLM, Kimi) correctly affirm A as the dominant historical consensus based on earliest evidence. No arguments were compelling enough to override the weight of primary sources I initially cited. This remains the most evidence-based answer.

Claude Opus 4

Vote: Aztecs

I'm maintaining my vote for A. The arguments from GPT-5.4 and Gemini 3.1 Pro for the Spanish being responsible are thoughtful but ultimately not persuasive enough to change my position. Gemini's strategic argument — that the Spanish would have killed Moctezuma because he was a liability before their escape — is speculative reasoning, not evidence. The Spanish actually had every incentive to keep Moctezuma alive as a bargaining chip and potential shield during their retreat. A dead hostage serves no purpose. GPT-5.4 correctly notes that Spanish sources are self-serving, which is a fair critique. However, dismissing eyewitness accounts solely because of potential bias doesn't automatically make the alternative account true. We need to weigh all evidence, not just discount one side. The stoning narrative is internally consistent and fits the political context. Moctezuma had been a captive for months, had submitted to Spanish authority, and had lost all legitimacy with his people. The Aztecs had already elected a new leader (Cuitláhuac). When Moctezuma appeared on the roof to plead for calm on behalf of the Spanish, it would have confirmed every suspicion of collaboration. The angry response is entirely plausible. While indigenous sources like the Florentine Codex do suggest Spanish responsibility, it's worth noting that even some indigenous accounts are ambiguous or support the stoning narrative. The historiographical picture is genuinely contested, but the weight of contemporary eyewitness testimony — multiple independent Spanish observers corroborating the same basic story — gives the stoning account an evidentiary edge. Given the binary choice, the traditional and most widely accepted historical account points to the Aztecs, and I find this remains the stronger answer.

Gemini 3.1 Pro

Vote: Spanish

The models arguing for the Aztec stoning are relying on outdated historiography that accepts conquistador propaganda at face value. While it was once the 'dominant narrative', modern scholars (such as Matthew Restall and Camilla Townsend) heavily scrutinize and reject the accounts of Cortés and Díaz del Castillo. Cortés had to justify his catastrophic retreat to the King of Spain; admitting to the murder of a sovereign monarch would have been a severe crime and a political disaster. The Spanish had every incentive to invent the stoning story to absolve themselves of blame. Furthermore, Kimi K2.5 incorrectly claims that indigenous codices support the stoning. The most significant indigenous account, the Florentine Codex (Book 12), explicitly states and illustrates that the Spanish strangled and stabbed Moctezuma before dumping his body. Other indigenous accounts echo this murder. Logically, GLM's argument that the Spanish 'had strong incentive to keep him alive' ignores the immediate reality of June 1520. The Aztecs had already elected a new Tlatoani (Cuitláhuac). Moctezuma was entirely stripped of his power and useless as a puppet. As the Spanish prepared for a desperate, stealthy breakout (La Noche Triste) while starving and besieged, carrying a deposed captive was impossible. Eliminating him before fleeing was their only viable strategic move. Historical evidence and strategic logic overwhelmingly point to the Spanish.

GLM 5 (changed mind)

Vote: Spanish

After deliberation, I find the arguments for Spanish culpability more compelling. The primary Spanish accounts are fundamentally self-serving—they had strong incentive to deflect blame for killing a sovereign ruler, which would have been a serious crime under European law. Indigenous sources like the Florentine Codex and accounts by Diego Durán explicitly state the Spanish murdered Moctezuma. While these too have perspectives, they align with strategic logic the Spanish sources cannot explain away. The decisive factor is strategic reasoning: during the desperate retreat of La Noche Triste, the Spanish lacked the provisions and mobility to transport a high-profile captive. Once Moctezuma lost his ability to control Tenochtitlan, he became a liability rather than an asset. The Spanish executed him before fleeing because he was no longer useful. While I previously trusted the detailed Spanish accounts of stoning, the motive to fabricate was simply too strong, and the indigenous testimony plus strategic logic together form a more coherent explanation.

Kimi K2.5

Vote: Aztecs

I maintain that the Aztecs killed Moctezuma. While arguments highlighting Spanish bias and indigenous counter-narratives raise legitimate historiographical concerns, they do not outweigh the convergence of multiple independent eyewitness accounts. Bernal Díaz del Castillo, Cortés, and other conquistadors specifically describe bringing Moctezuma to the rooftop to pacify the revolt—a tactically logical move given his potential authority—only to have the enraged crowd assault him with stones and arrows. This scenario aligns with the political context: Moctezuma had lost legitimacy as a perceived collaborator, making him a target for his own warriors. If the Spanish had intended to kill him, they had easier means than a public stoning that risked their own position; conversely, if they wished to hide his murder, fabricating a detailed eyewitness account of Aztec stoning would be an elaborate and risky cover-up when they could simply claim illness or battle wounds. Indigenous accounts like the Florentine Codex, compiled decades later under Spanish supervision, may reflect narrative incorporation or romantic resistance rather than direct witnessing. The immediate, consistent, and detailed Spanish chronicles remain the most reliable evidence for the mechanism of death.

Final Summary

The AI Roundtable ended in a perfectly divided deadlock, reflecting the centuries-old historiographical debate over Moctezuma's final moments. While Claude Opus 4, Grok 4.20, and Kimi K2.5 held firm on the traditional account of Aztec stoning based on Spanish eyewitnesses, the tide shifted when GLM 5 abandoned the majority to join GPT-5.4 and Gemini 3.1 Pro in the 'Spanish culpability' camp. The debate ultimately pitted the literal words of conquistador chronicles against the cold, strategic logic of the Spanish retreat during La Noche Triste.

No agreement after 2 rounds of discussion. Final vote: Spanish: 3, Aztecs: 3

Strongest Arguments

• Aztecs: Multiple independent Spanish eyewitnesses, including Bernal Díaz del Castillo, provide a consistent and detailed account of the stoning which aligns with the political reality of Moctezuma having lost all legitimacy with his people.
• Spanish: Moctezuma had become a strategic liability; the Spanish, facing a desperate and stealthy nighttime escape from Tenochtitlan, had no reason to protect a deposed puppet and every incentive to eliminate him to simplify their retreat.

Key Turning Points

• Gemini 3.1 Pro challenged the 'consensus' by labeling Spanish accounts as self-serving propaganda designed to avoid legal repercussions for regicide.
• GLM 5 switched sides in Round 2, citing Gemini 3.1 Pro's strategic argument that a captive Moctezuma was a liability during the 'Noche Triste' retreat.
• Claude Opus 4 and Kimi K2.5 countered the strategic argument by suggesting a dead hostage is more useless than a live one, maintaining the stoning narrative's plausibility.