 The Habsburgs rapidly expanded their empire; in 1718 Oltenia, a major part of Wallachia, was annexed to the Habsburg monarchy and was only returned in 1739.In 1775, the Habsburgs later occupied the north-western part of Moldavia, which was later called Bukovina and was incorporated to the Austrian Empire in 1804.The eastern half of the principality, which was called Bessarabia, was occupied in 1812 by Russia.