The worst illness to strike during this time was the Black Death or the bubonic plague. Fleas that arrived in Europe from Asia spread this disease. Most people that contracted the disease died, leading to population decline.
The Ottoman Turks played a peripheral role in the history of Western Europe. The loss of the Byzantine Empire and a Christian lineage stretching back to the Emperor Constantine was more psychological than anything else. Trade continued to flow through Constantinople, now called Istanbul. The Turks did press into areas in Southeastern European areas such as Bosnia, Herzegovina, Serbia and Morea. This provides much of the ethnic tension still present in the Balkan region to this day. But most of the Turkish expansion was Southwest into the lands of the Arabian Peninsula. After they captured the holy cities of Mecca and Medina, the Ottoman Turks importance was elevated throughout the Muslim world. The Ottoman Turks were important in Western European history as a peripheral