How did Thucydides investigate events of the Peloponnesian War?

Thucydides investigated the events of the Peloponnesian War by prioritizing rigorous, scientific inquiry over general impressions or "storytelling". His methodology was defined by several key principles:12

• Critical Evaluation of Sources: When reporting events he did not personally witness, he carefully cross-referenced reports from eyewitnesses, remaining acutely aware that their accounts could be distorted by bias or faulty memory.12
• Direct Observation: For battles he observed himself, he conducted as thorough an investigation as possible to ensure accuracy.1
• Chronological Precision: He adhered to a strict chronological framework, which has been validated by modern testing against recorded astronomical events like eclipses.3
• Use of Speeches: While he wrote speeches in his own words, he aimed to capture the general sense of what was actually said to explain the motives and ambitions of historical figures.1
• Impartiality: He maintained a passion for truth, avoiding "vulgar partiality" even when writing about his own side, and he did not use his history to defend his own military failures.3

His ultimate goal was to create a lasting, useful analysis of human nature in times of conflict.12