Despite conservative intentions, the conquests, the settlement of large Arab-Muslim populations in numerous garrisons, and the consolidation of a new imperial regime set in motion vast changes in the patterns of international trade, local commerce, and agriculture. The unification of former Sasanian and Byzantine territories removed political and strategic barriers to trade and laid the foundations for a major economic revival. The Euphrates frontier between the Persian and the Roman worlds disappeared, and Transoxania, for the first time in history, was incorporated into a Middle Eastern empire. Commercial considerations inspired Arab-Muslim expansion in Inner Asia and India. Cities prospered in Iraq, Iran, and Transoxania. Basra and later Baghdad became two of the leading trading cities in the world. Samarqand, Bukhara, and Nishapur prospered. However, a new frontier was drawn between Syria and Anatolia, which had formerly been part of a single Byzantine state, and trade between these regions declined.

Each region of the new empire fared differently under Arab-Muslim rule. Some prospered, some declined. Agricultural production shifted from one area to another. Arab-Muslim landowners often replaced the previous elites. Soldiers settled on the land, and non-Arabs moved to Arab settlements. These changes created a high degree of mobility and interaction between different peoples and set the basis for the ultimate integration of populations into a shared culture.