Kayalyk, ancient seat in Kazakhstan, on the Silk road

Kayalyk is a ruined medieval city on the Aschybulak River east of the village of Koylyk. Its earthen wall stands 3.5–4.5 m high, with a northeast side 1,200 m long and a southwest side 750 m long. Round towers survive along the wall at 30–40 m intervals, some still 6–8 m tall.

Kayalyk appears in 11th–13th-century sources as the capital of the Karluk jabghu within the Karakhanid realm. In autumn 1253 the Franciscan envoy William of Rubruck stayed twelve days, waiting for a secretary of Batu, and left on St Andrew's Day. The Semirechye expedition surveyed the site in 1964; in 1997 K. M. Baipakov's Turkestan expedition excavated it.

The settlement served as a meeting place where different religions coexisted peacefully for centuries. Excavations have revealed remains of Buddhist temples, a cathedral mosque, Christian churches, and Manichaean sites, showing how diverse communities shared this space and influenced each other through daily interaction.

The ruins lie east of Koylyk village (formerly Antonovka), on the bank of the Ashchybulak river in the Sarkand district. The enclosing wall survives on two sides, with the northeast side running 1200 m and the southwest 750 m; round towers stand every 30-40 m, some still 6-8 m high. Ground is open and unshaded, so bring water and sun protection.

The French ambassador Wilhelm Rubruk visited the city in the 13th century and documented its diverse population and active markets, providing rare written testimony to its importance. This firsthand account from a Western medieval observer makes Kayalyk one of the few Central Asian sites with direct historical confirmation from outside sources of the era.