Battle of Kosmidion

The Battle of Kosmidion, fought June 15, 1410, occurred during the Ottoman Interregnum and was fought between the forces of the brothers and princes Musa Çelebi and Süleyman Çelebi, just outside the land walls of Constantinople. During the battle, some of Musa's vassals, including Vuk Lazarević (the brothers' half-uncle), deserted him and joined Süleyman. It ended in a victory for Süleyman Çelebi.