Xanthos, the capital city of the Lycian Federation, was built in the valley of the Xanthos River. There are no definitive records of the exact date of its founding. As mentioned in The Iliad, King Sarpedon crossed the Xanthos River with his soldiers—but no further details are given. Like other Lycian cities, Xanthos was an independent state until the Persians invaded. In 545 B.C., they surrounded the city. The residents bravely defended it, but realized that they could not resist the invasion nor the ruler, King Harpagos, the men of Xanthos gathered their wives, children, and possessions in the acropolis, set fire to all, then rushed out fighting, to die to the last man.

About 80 families, who were out of the city during these events, returned and rebuilt Xanthos.

In 43 B.C., Brutus attempted to take control of Xanthos during the Roman Civil Wars. As before, Xanthians chose mass suicide over submission. The Romans later took control of Lycia, and repaired the destroyed city. Antonius, who defeated Brutus, took over Rome’s eastern territories and gave the Lycians their freedom. Following two catastrophic earthquakes, Lycia began to decline.

The spread of Christianity brought more social and cultural changes to Lycia, and many cities became Byzantine settlements. Xanthos itself was the seat of an archbishop in the 8th century. It was abandoned during the first wave of Arab raids, which eventually brought the Lycian civilization to a close.

The most interesting ruins in Xanthos are the Roman theatre and the buildings. There is also an impressive monument, originally a sarcophagus, on a rock. The original relief is in the British Museum.