Philadelphia was a prosperous Byzantine city, called the "little Athens" in the 6th century AD because of its festivals and temples. Presumably this indicates that the city wasn't entirely converted to Christianity. Ammia, the Christian prophetess, was from Philadelphia, however. In about the year 600 the domed Basilica of St. John was built, remains of which are the main archaeological attraction in the modern city. The Byzantine walls that once surrounded the city have all but crumbled away. A few remnants are still visible at the northeast edge of town, near the bus stand. The city was taken by the Seljuk Turks in 1074 and 1093–94. In 1098, during the First Crusade, it was recovered by Byzantine Emperor Alexios I. In the 11th to 15th centuries AD, it was the seat of the "doux" (governor) and "stratopedarches" (military commander) of the Thrakesion theme.