Answer:
Trade and commerce were essential components of the success and expansion of the Byzantine Empire. Trade was carried out by ship over vast distances, although for safety, most sailing vessels were restricted to the better weather conditions between April and October. On land, the old Roman road system was put to good use, and so by these two means goods travelled from one end of the empire to the other, as well as from far-away places such as modern-day Afghanistan, Russia, and Ethiopia. The bigger cities had thriving cosmopolitan markets, and Constantinople became one of the largest trading hubs in the world where shoppers could stroll down covered streets and pick up anything from Bulgarian linen to Arabian perfumes.