Bulgaria's war aims were focused on Thrace and Macedonia. For the latter, Bulgaria had a secret agreement with Serbia to divide it between them, signed on 13 March 1912 during the negotiations that led to the establishment of the Balkan League. However, it was not a secret that Bulgaria's target was the fulfillment of the never-materialized Treaty of San Stefano, signed after the Russo-Turkish War, 1877–78. They deployed their main force in Thrace, forming three armies. The First Army, under Gen. Vasil Kutinchev with three infantry divisions, was deployed to the south of Yambol, with direction of operations along the Tundzha River. The Second Army, under Gen. Nikola Ivanov with two infantry divisions and one infantry brigade, was deployed west of the First and was assigned to capture the strong fortress of Adrianople (now Edirne). According to the plans, the Third Army, under Gen. Radko Dimitriev, was deployed east of and behind the First and was covered by the cavalry division hiding it from the Turkish view. The Third Army had three infantry divisions and was assigned to cross the Stranja mountain and to take the fortress of Lozengrad (Kirk Kilisse). The 2nd and 7th divisions were assigned independent roles, operating in western Thrace and eastern Macedonia, respectively.