That would be the Austrian Empire.
The Kingdom of Hungary became a part of the Austrian Empire and was rule by the Habsburg dynasty from 1526. In 1526, the Battle of Mohacs happened between the Kingdom of Hungary and Ottoman Turks and saw the Turks emerge victorious. This led to partitioning of the Kingdom of Hungary with one part going to the Turks, one to the Principality of Transylvania and the most importantly to the Austrian Empire which held the what was left of the Hungarian throne.