The inland city of Barda was already a major commercial center for overland trade when the Arab conquests in the seventh to eighth centuries wrested the Caucasus from. and finally toppled. Inclusion of Azerbaijan into the Arab Caliphate thereafter brought trade from the central Islamic lands into the Caucasus, both to its overland routes and the Volga-Caspian route, which was then less significant. Especially important in the growth of the Volga-Caspian route was Arab trade with the northern Slavs and. It was also in the 10th century that descriptions of oil in the Baku area were recorded by Arab geographers. Mas'udi wrote that nowhere else in the world could one find oil like that in Baku.
Coin hoards found in Azerbaijan attest to the vigorous international trade of the area.
The creation of the Mongol Empire in the 13th and 14th centuries, though inaugurated by terrible destruction, resulted in the imposition of uniform laws, security of goods and person. Archaeological excavations of the 1970s in Baku's inner city unearthed a caravan saray of skillfully carved stone from the 15th century. Among the inscriptions on the stones are several in Sanskrit, indicating the distance from which merchants traveled to Baku. Both partners shared animosity toward the Ottoman Turks. Muscovy despised the Turks because of Ottoman support of Crimean Tatars and Poles who raided Russian towns and habitually burned Moscow.