Scientists and historians are still unsure about the origins of plague. Medieval European writers believed that it began in China, which they considered to be a land of almost magical happenings. Chroniclers wrote that it began with earthquakes, fire falling from the sky, and plagues of vermin. Like medieval travel literature, these accounts are based on a number of myths about life in areas outside of Europe. It now seems most probable that infected rodents migrated from the Middle East into southern Russia, the region between the Black and Caspian seas. Plague was then spread west along trade routes. There were epidemics among the Tartars in southern Russia in 1346. Plague was passed from them to colonies of Italians living in towns along the Black Sea. Merchants probably carried the disease from there to Alexandria in Egypt in 1347; it then moved to Damascus and Libya in 1348, and Upper Egypt in 1349. Venetian and Genoese sailors are known to have brought the plague to Europe.