In the century after the death of Osman I in 1326, Ottoman rule began to extend over the eastern Mediterranean and the Balkans, slowly at first and later in earnest. Gallipoli was captured in 1354, severing the Byzantine Empire from its continental territories; the important city of Thessaloniki (with a greater population than London at the time) was captured from the Venetians in 1387, and the Turkish victory at the Battle of Kosovo in 1389 effectively marked the end of Serbian power in the region, paving the way for Ottoman expansion into the rest of Europe.