Alexander (Alexander of Battenberg), 1857–93, prince of Bulgaria (1879–86); second son of Prince Alexander of Hesse-Darmstadt and nephew of Alexander II of Russia. He served in the Russian army against the Turks (1877–78) and, backed by the Rus sian czar, was elected hereditary prince of Bulgaria under Turkish suzerainty. In 1885 the revolutionaries in Eastern Rumelia, also known as Southern Bulgaria, proclaimed the union of that province with Bulgaria. Alexander accepted the union, thus incurring the wrath of the Russian czar and Serbia. The latter declared war. Alexander was victorious and by an agreement with Turkey became governor of Eastern Rumelia, but he was forced to abdicate by a group of officers. He became an Austrian officer, and Ferdinand was elected to succeed him as prince.