The First Battle of Çatalca fought between was one of the heaviest battles of the First Balkan War. It was initiated as an attempt of the combined Bulgarian First and Third armies, under the overall command of lieutenant general Radko Dimitriev, to defeat the Ottoman Çatalca Army and break through the last defensive line before the capital Constantinople. The high casualties however forced the Bulgarians to call off the attack and allow their adversary to claim victory. This was the greatest military success of the Ottoman Army for the entire duration of the war and the first major defeat of the Bulgarian Army since its establishment in 1878.