This article is about the noble family, for other meanings see Habsburg (disambiguation).

The Habsburgs (also House of Habsburg, House of Austria and Casa de Austria) are a princely dynasty named after their ancestral castle in what is now the Swiss canton of Aargau. From the late Middle Ages onwards, they rose to become the most powerful dynasty in Europe, alongside - and in competition with - the Capetians, for half a millennium, and also ruled a colonial empire via the kingdoms of Spain and Portugal.

The designation "House of Austria" was transferred from the country, the Duchy of Austria to the Habsburgs in the 14th century. This designation then transferred to the lands ruled by the Habsburgs. The upgrading of the Austrian duchy to an archduchy was accompanied by the designation of the ruling family as the Archhouse. It was the only dynasty in the world to use the title archduke (created by itself).

The Habsburgs initially had major landholdings in Upper Alsace between Basel and Strasbourg. In October 1273, Rudolf I became the first Habsburg to be elected king of the Holy Roman Empire. He finally defeated his rival Ottokar of Bohemia, who had opposed him in the royal election, five years later at the Battle of the Marchfeld (August 26, 1278) east of Vienna. After the victorious battle in which Ottokar fell, Rudolf I placed the duchies of Austria, Styria and Carniola occupied by Ottokar under his rule and initially administered them himself. By leaving Ottokar's original dominions of Bohemia and Moravia with his son Wenceslas II and marrying him to one of his daughters, he strengthened the Habsburgs' domestic power.

In 1283 Rudolf I granted the duchies of Austria and Styria as fiefs to his sons Albrecht I and Rudolf II, thus bringing about the rise of his house from the rank of count to that of prince. By mutual agreement, Albrecht I administered Austria and Styria alone, while Rudolf II retreated to the old family estates in Aargau and Upper Alsace.

After the last Meinhardiner, Heinrich von Kärnten, died on May 2, 1335, Emperor Ludwig the Bavarian transferred the duchies of Carinthia and Carniola to the Dukes of Austria, Albrecht II and his brother, Otto the Merry, as imperial fiefs. In 1363, Duke Rudolf IV also succeeded in bringing Tyrol to the Habsburgs.

From 1438 and 1526/1527 respectively, Bohemia, Croatia and parts of Hungary came under Habsburg rule. With the Bohemian crown, the electorship and thus one of seven votes in the college electing the Roman-German king finally fell to the Habsburgs in 1526. From 1439 to 1806, the House of Habsburg provided the German kings and Roman-German emperors almost without interruption.

In the 16th century the dynasty divided into a Spanish line, which ruled over Spain and Portugal and their overseas possessions in America, Africa and Asia, and whose male line died out in 1700 with Charles II, and an Austrian line, whose male line ended in 1740 with Charles VI. ended, but was continued by his Pragmatic Sanction, which he sought to secure with his neighbors, namely by the descendants of his eldest daughter Maria Theresa (but the arrangement did not apply to the head of the Holy Roman Empire, who had to be a man). Maria Theresa founded the House of Habsburg-Lorraine through her union with Francis I Stephen of the House of Lorraine, who as Francis I attained the imperial dignity in the Empire. In this house the Roman-German imperial dignity remained until the end of the empire in 1806. The last Roman-German emperor, Francis II, founded the Empire of Austria in 1804 as Francis I of Austria, which was transformed into the Dual Monarchy of Austria-Hungary in 1867/68 and existed until 1918. After 1918, the Habsburgs had to renounce their claims to rule in both Austria and Hungary.

At times, the Habsburgs also ruled over other European territories, including the Habsburg Netherlands and the Free County of Burgundy, in Upper Italy over Milan and parts of Lombardy, and over the lands in Upper Germany formerly known as Vorderösterreich. Secondary lines ruled Tuscany, Modena and Parma from the 18th century onward, and Mexico for a short time in the 19th century.

Since 2007, the head of the family has been Karl Habsburg-Lothringen as the eldest son of Otto von Habsburg, the last Crown Prince of Austria-Hungary.