The 11th–14th centuries represent a period of prosperity for the city, as shown in archaeological evidence of renewed activity both in the harbour as well as the hinterland and the area of the citadel. It became an important location for trading on the Silk Road in the 12th and 13th centuries, as a terminus for Black Sea trade. The 14th-century Arab traveller Ibn Battuta even compares its harbour with that of Alexandria. The 13th-century chronicler Ibn al-Athir writes of it as the "city of the Qifjaq from which (flow) their material possessions. It is on the Khazar Sea. Ships come to it bearing clothes. The Qifjiqs buy from them and sell them slaves. Burtas furs, beaver, squirrels ..."