The Vardar Offensive that took place between 14 and 29 of September 1918 was the last major military operation on the Macedonian Front during World War I.After much preparation the multinational Allied Army of the East was able to break the deadlock that had been reigning on this theater for several years, by breaking through the enemy lines in the Battle of Dobro Pole on 14-15 September.After this victory, the Entente army continued to liberate southern Serbia.