Ankyra (modern Ankara) was a civil and ecclesiastical metropolis of Galatia. Ankyra's strategic location on the main highway across Anatolia made it a center of trade and a major military base. Frequently visited by emperors, it was an imperial summer residence in the late 4th and early 5th century.

In the 4th century, Ankyra was the seat of a cultivated pagan landowning aristocracy; they were closely connected with the governors, who frequently adorned the city with public works. The local ruling class became Christian only in the 5th century, when the rich were famed for their piety and philanthropy. In the 6th century, the governor, bishop, and local magnates dominated Ankyra; its population was devoted to St. Theodore of Sykeon , who reportedly wrought many miracles in the city. Ankyra remained peaceful and prosperous through the early 7th century. In 610-611 it was the base of the revolt of Komentiolos . Sources attest a large range of public buildings, both pagan and Christian; few survive.

In 622, the Persians captured and destroyed Ankyra; afterward the large area of the ancient city was abandoned and Ankyra retreated to its heavily fortified acropolis. It became capital of the Opsikion theme in the 7th century and of the Boukellarion in the 8th century. The frequent goal of Arab attacks, Ankyra fell to al-Mutasim in 838, was rebuilt by Michael III in 859, and taken by the Paulicians in 871. After the Turks captured it around 1080, Ankyra only briefly returned to Byzantine rule following the Crusade of 1101.

An important center of Christianity, Ankyra was the home of saints Plato and Clement and the site of councils in 314, 358, and 375. The council of 325, planned for Ankyra, was transferred to Nicaea. The site contains scattered remains of civic buildings, including a large bath that functioned until the 7th century; traces of luxurious houses, and the Church of St. Clement, a cross-domed brick structure (8th/9th century?). Its fortress, one of the greatest of Anatolia, consists of a citadel, an upper rampart with closely spaced pentagonal towers, and an extensive lower wall. The inner fortress apparently dates to the mid-7th century, the outer to the early 9th century; all were rebuilt by Michael III.