---
node: thucydides
type: person
slug: thucydides
title: "Thucydides"
lead: "Thucydides (c. 460–c. 400 BC) was the Athenian general and historian whose unfinished History of the Peloponnesian War set explicit standards of evidence. He is often called the founder of scientific history and of political realism."
published: 2026-07-10
updated: 2026-07-10
---

## Who they were

Thucydides (c. 460–c. 400 BC) was an Athenian general and the historian of the Peloponnesian War. He caught the plague that struck Athens and survived; his clinical description of it is famous. As a general he failed to save Amphipolis from Brasidas in 424 BC and was exiled for twenty years — by his own account, the exile let him observe the war from both sides.

## What they did

He wrote the History of the Peloponnesian War, left unfinished and breaking off mid-sentence in 411 BC; Xenophon's Hellenica picks up the story. He stated his standards of evidence — his own observation and cross-examined eyewitnesses — while the speeches, by his own admission, are reconstructed to fit what each occasion called for. He excluded the mythical, aiming, as he put it, at a possession for all time rather than a prize-piece for the moment. His analysis made power, fear, and interest the drivers of events: the judgment that Sparta was driven to war by fear of Athens' growth, and the Melian Dialogue on the strong and the weak, are his set-pieces.

## Legacy

Thucydides is often called the founder of scientific history and of political realism. He is read continuously in war colleges and in political theory, and the coinage of a Thucydides trap in modern debate shows his afterlife.