Wine has been traded as a commodity since 1600 BC when Greeks first began producing and trading various wines throughout locations in France, around the Black Sea, and in the Danube region. During the ancient Greek period, large quantities of wine were shipped along the Mediterranean in ceramic jars, with over 2.2 million gallons traded annually through the port of Marseilles alone. In later centuries, wine trading expanded significantly to regions in southern and eastern England, the Low Countries, Scandinavia, and became an important part of social, religious, and medical customs in Roman society. The development of wooden barrels improved long-distance wine trading and transportation.