SURFACE ruptures have been identified for some normal-faulting earthquakes in the Aegean region1-3, but for most historical earthquakes the associated faults are unknown. This hampers the evaluation of the rates and styles of present-day deformation, and the assessment of seismic hazard in the region4. Here we examine the famous earthquake that destroyed Sparta in 464 BC. Using SPOT satellite images and fieldwork, we have mapped a 20-km-long normal fault scarp trending approximately north-south, a few kilometres east of the ancient city. Our observations, combined with an examination of historical descriptions of the earthquake damage, suggest that the Sparta earthquake ruptured this fault scarp in an event of magnitude Ms ~ 7.2. The Holocene slip rate and the recurrence time for such large events on the Sparta fault would be ~1 mm yr-1 and ~3,000 yr, respectively.