Kiev (Кий, modern Kyiv) is a historic town on the middle Dnieper. It appears in Middle sources as main base for the expeditions of the Rus’ to Constantinople. Exports from Constantinople and the Crimea to and through Kiev included coins, glass, and amphoras with wine and oil. From the mid-10th to the mid-12th century, Kiev was in effect the capital of the Rus’ and the main channel for political, economic, and cultural contacts with the Byzantines. The metropolis of Rhosia (Ῥωσία) was established at Kiev around 888. Connections with Constantinople can be seen in the seals of the princes and metropolitans being inscribed in Greek. Byzantine builders also constructed a number of churches, including the churches of St. George, St. Irene, the Annunciation, and the Church of the Dormition in the monastery of the Caves. From the mid- 12th century, the political authority of Kiev was generally limited to its own principality. Kiev retained its status as the ecclesiastical capital, however, even after its sack by the Mongols (1240) and the rise of Lithuania and Moscow.