 Among them, they had several thousand modern heavy cavalry, some units of light cavalry, and majority were men-at-arms.In addition, there was a large contingent, of close to 15,000 Ottoman Turks under Isa-Beg that came to fight on the Bosnian side, arriving just in time from direction of Zenica and Lasva Valley.Encroaching Ottomans were already a real threat to Southeastern Europe since the fall of Serbian Empire in 1371.