The House of Habsburg, also called House of Hapsburg,or House of Austria, is one of the most influential and outstanding royal houses of Europe.

The throne of the Holy Roman Empire is continuously occupied by the Habsburgs between 1438 and 1740.

The house also produces emperors and kings of the Kingdom of Bohemia, Kingdom of England (Jure uxoris King), Kingdom of Germany, Kingdom of Hungary, Kingdom of Croatia, Second Mexican Empire, Kingdom of Ireland (Jure uxoris King), Kingdom of Portugal, and Spain.

From the sixteenth century, following the reign of Charles V, the dynasty is split between its Austrian and Spanish branches.

Although they rule  distinct territories, they nevertheless maintain close relations and frequently intermarry.

The House takes its name from Habsburg Castle, a fortress built in the 1020s in present-day Switzerland, in the canton of Aargau, by Count Radbot of Klettgau, who chooses to name his fortress Habsburg.

His grandson Otto II is the first to take the fortress name as his own, adding "Count of Habsburg" to his title.

The House of Habsburg gathes dynastic momentum through the eleventh, twelfth, and thirteenth centuries.

By 1276, Count Radbot's seventh generation descendant Rudolph of Habsburg has moved the family's power base from Habsburg Castle to the Duchy of Austria.

Rudolph had become King of Germany in 1273, and the dynasty of the House of Habsburg is truly entrenched in 1276 when Rudolph becomes ruler of Austria, which the Habsburgs rule until 1918.

A series of dynastic marriages enable the family to vastly expand its domains to include Burgundy, Spain and its colonial empire, Bohemia, Hungary, and other territories.

In the sixteenth century, the family separates into the senior Habsburg Spain and the junior Habsburg Monarchy branches, who settle their mutual claims in the Oñate treaty.

The House of Habsburg becomes extinct in the eighteenth century.

The senior Spanish branch ends upon the death of Charles II of Spain in 1700 and is replaced by the House of Bourbon.

The remaining Austrian branch becomes extinct in the male line in 1740 with the death of Holy Roman Emperor Charles VI, and completely in 1780 with the death of his eldest daughter Maria Theresa of Austria.

It is succeeded by the Vaudemont branch of the House of Lorraine.

The new successor house styles itself formally as the House of Habsburg-Lorraine (German: Habsburg-Lothringen), and because it is often confusingly still referred to as the House of Habsburg, historians use the unofficial appellation of the Habsburg Monarchy for the countries and provinces that are ruled by the junior Austrian branch of the House of Habsburg between 1521 and 1780, then by the successor branch of Habsburg-Lorraine until 1918.