Xanthos, described by Strabo as Lycia's largest city, takes its name from the river that flows beside it, the Xanthos (today's Esen Çayı), which means "yellow" in Greek. Its oldest name, however, appeared as 'Arnna' in ancient written sources and on coinage.

Homer states that one of the heroes in the Trojan War, a man named Sarpedon, came from Xanthos, However, the earliest finds discovered in French excavations of the city, in progress since 1950, date to the eighth century B.C.

Xanthos maintained its independence until 545 B.C., when it was razed in the course of the Persian invasion under the command of Harpagos. In spite of their defeat, Xanthians passion for heroism and honour was immortalized in the pages of history. Herodotus describes the horror of these events and the terrible fate of the Xanthians thus: "Harpagos, marching to the Xanthos plain at the head of his forces, in spite of their small numbers, performed many honourable deeds. In the end, when they understood that they would be defeated, they retreated behind the city walls and set fire to their wives, children, slaves, and their goods, reducing all to ashes. And after this, they hurled themselves on their enemies. Except for 80 families who were not present in the city during the battle, all of the Xanthians perished."

As a result of excavations, it is also known that some time between the years 475 and 470 B.C. Xanthos suffered another major calamity when its acropolis burned to the ground. After this fire the city was rebuilt, and, expanding rapidly, it soon developed into a centre which had contact with the western world.

With the invasion of Alexander the Great, Xanthos undoubtedly again went through troubled times.

Still another bitter chapter in this disaster-filled history was Brutus' occupation of the city in 42 B.C. during Rome's civil wars. Written sources describe these events in great detail. The Xanthians, forewarned of Brutus' attack surrounded the city with a deep trench, destroying the quarters that lay outside it so as to leave no provisions for the Romans. Brutus, while attacking the walls from one side, marched his infantry to the gates. The people, in spite of their exhaustion and the fact that nearly all of them were wounded, continued to defend the city. Then the neighbouring people of Oinoanda, in an act of treachery against the citizens of Xanthos, showed the enemy the ways by which the city could be entered. When Xanthos was on the point of being captured, the people ran to their homes and voluntarily killed their families. They speared the envoys Brutus sent to them to offer a truce and threw themselves on pyres they had made, set fire to them, and died in the flames. Excluding slaves, Brutus was able to take only a few women and 150 men. The Xanthians fought to the death against the powerful Roman armies to protect their freedom, and in doing so demonstrated their great courage one last time.

Under Roman domination, whether with the contributions of Rome or of wealthy Lycians, Xanthos developed rapidly and succeeded in recreating its former brilliance. Later, during the Byzantine period, the city became the seat of a populous bishopric, but it was finally destroyed once and for all by Arab raids in the seventh century.

Xanthos was first investigated in 1838 by Sir Charles Fellows, who took a large number of the works of art he had discovered back to the British Museum in London.

The city's main centre was the Lycian acropolis that rises straight up from the bank of the river Xanthos (today's Eşen Çayı). On its east west and south sides, the acropolis is enclosed by fifth century B.C. city walls in polygonal masonry. The northern wall dates to the Byzantine era. Xanthos' earliest remains are located in the south-east corner. One of the structures here, a building of square plan comprised of several interconnecting rooms, is thought to have been a palace destroyed in the course of Harpagos' invasion. Buildings were constructed on top of the palace ruins during the period of Persian domination, however, one can clearly see that these met with a fire.

On reaching the highest point of the acropolis, one encounters a temple with a rectangular plan; only the large stone blocks of its foundation survive today. It is unfortunate that, a number of the structures like this in the acropolis suffered extensive damage, and that their building materials were subsequently reused in a variety of other places.

Located immediately in front of the Byzantine walls is a second century A.D. Roman theatre that was in all probability built atop a pre-existing theatre of Hellenistic date. The tiers of seats are in a fairly good state of preservation. The orchestra, full of stones from the stage building, which is in a ruinous state, is entered from the east via a vaulted parados. The western parados serves only as a stage exit and does not open to the outside.

On the west of the theatre are two famous, magnificent Lycian sepulchral monuments standing side by side. The first of these, which is 8.87 metres high and is known as the Harpy Tomb because of a relief frieze carved on it, consists of a small funerary chamber surrounded on all four sides by a massive stone pillar. This chamber is covered at the top with a stone slab. The tomb's marble reliefs were taken by Fellows to London in 1842. The reliefs now seen in their place are plaster copies cast from the originals. The subject of these reliefs, as difficult to understand as it is interesting, is the presentation of gifts by family members to the owner of the tomb and his wife. On the north and south sides, fantastic creatures called harpies-half bird, half woman-carry the souls of the dead, represented as children, toward the heavens. The monument dates to 480-470 B.C.

Next to the Harpy Tomb is another tomb of a somewhat different type. This example, measuring 8.95 metres high in its entirety, dates to the fourth century B.C. It consists of a pillar made up of large stone slabs covered by a three-stepped roof, with a Lycian-style sarcophagus at the summit.

The most important ruin in Xanthos is the Inscribed Obelisk, situated behind the north portico of the agora. The monument, dated 425-400 B.C., is an inscribed monolith rising atop a two-stepped krepis. From fragments found during excavations, it has been determined that this was originally a monumental tomb some 11 metres high, consisting of the existing pillar, on top of which was a burial chamber encircled, like the Harpy Tomb, by relief friezes. On top of this was a horizontal stone roof crowned by a statue of a prince seated on a lion-shaped throne. The inscription, which is on all four faces of the pillar and is more than 250 lines long, is the longest known Lycian inscription and gives important information about the period's history. According to the inscription, the monument was erected to commemorate the battles and victories of a Lycian prince named Kherei.

On the descent from the acropolis, there is a beautiful Hellenistic tower and an ancient stone-paved road leading to one of the city gates from the direction of the sea. An inscription containing the name Antiochos dates the gate. An archway behind the gate is dedicated to the Emperor Vespasian (69-79 A.D.).A little further to the north we can see some stone blocks of a podium, all that remains in situ of a famous heroon in the form of an lonic temple. This building is known in archaeological literature as the Nereid Monument. Almost all of the rest of the monument, dating to c. 400 B.C., is now in the British Museum.

In the Roman acropolis are the ruins of a huge monastery which has been excavated only recently. It has a large church, built in the Byzantine period on top of a Roman temple. The church's atrium and basilica are of the classical type with a nave and two side aisles. The trefoil baptistry in the north of the apse, with its marble pool and floor mosaics, is well worth seeing.

Several rock-cut tombs and monuments standing side by side in the south-east corner of the acropolis present an impressive sight. This site was the location of Lycia's oldest tomb usually known as the Lion Tomb, but sometimes mentioned by the name of its owner, a certain Payava. Today, all that can be seen of the tomb in situ are its foundation walls; the upper portions of the monument are now in the British Museum.