The other commodities that were traded, in Constantinople and elsewhere, were numerous: oil, wine, salt, fish, meat, vegetables, other alimentary products, timber and wax. Ceramics, linen, and woven cloth were also items of trade. Luxury items, such as silks, perfumes and spices were also important. Trade in slaves is attested, both on behalf of the state, and, possibly, by private individuals. International trade was practiced not only in Constantinople, which was until the late 12th century an important center of the eastern luxury trade, but also in other cities that functioned as centers of inter-regional and international trade, such as Thessaloniki and Trebizond. Textiles must have been by far the most important item of export; silks were certainly imported into Egypt, and they also appear also in Bulgaria and the West. The empire had also trading activity through Venice (as long as the latter was part of the empire): salt, wood, iron, and slaves, as well luxury products from the East, were the products exchanged. In 992, Basil II concluded a treaty with Pietro Orseolo II by the terms that Venice's custom duties in Constantinople would be reduced from 30 "nomismata" to 17 "nomismata" in return for the Venetians agreeing to transport Byzantine troops to Southern Italy in times of war. During the 11th and 12th centuries Italian trade in the empire took place under privileged conditions, incorporated in treaties and privileges that were granted to Amalfi, Venice, Genoa, and Pisa.