The Habsburg monarchy (, ), also known as the Danubian monarchy ( ), or Habsburg Empire ( ), was the collection of empires, kingdoms, duchies, counties and other polities that were ruled by the House of Habsburg, especially the dynasty's Austrian branch. The history of the Habsburg monarchy can be traced back to the election of Rudolf I as King of Germany in 1273 and his acquisition of the Duchy of Austria for the Habsburg in 1282. In 1482, Maximilian I acquired the Netherlands through marriage. Both realms passed to his grandson and successor, Charles V, who also inherited the Spanish throne and its colonial possessions, and thus came to rule the Habsburg empire at its greatest territorial extent. The abdication of Charles V in 1556 led to a division within the dynasty between his son Philip II of Spain and his brother Ferdinand I, who had served as his lieutenant and the elected king of Hungary and Bohemia. The Spanish branch (which held all of Iberia, the Netherlands, Burgundy, and lands in Italy) became extinct in 1700. The Austrian branch (which ruled the Holy Roman Empire, Hungary, Bohemia and various other lands) was itself split into different branches in 1564 but reunited 101 years later. The Habsburg monarchy was a personal union of crowns, with no uniform laws or shared institutions other than the Habsburg court itself; the territorial possessions of the monarchy were thus united only by virtue of a common monarch. The Habsburg realms were unified in 1804 with the formation of the Austrian Empire and later split in two with the Austro-Hungarian Compromise of 1867. The monarchy began to fracture in the face of inevitable defeat during the final years of World War I and ultimately disbanded with the proclamation of the Republic of German-Austria and the First Hungarian Republic in late 1918. In historiography, the terms "Austria" or "Austrians" are frequently used as shorthand for the Habsburg monarchy since the 18th century. From 1438 to 1806, the rulers of the House of Habsburg almost continuously reigned as Holy Roman Emperors. However, the realms of the Holy Roman Empire were mostly self-governing and are thus not considered to have been part of the Habsburg monarchy. Hence, the Habsburg monarchy (of the Austrian branch) is often called "Austria" by metonymy. Around 1700, the Latin term monarchia austriaca came into use as a term of convenience. Within the