Origins and expansion
The Habsburg family originated with the Habsburg Castle in modern Switzerland, and after 1279 came to rule in Austria. The Duchy of Austria was part of the elective Kingdom of Germany within the Holy Roman Empire. King Rudolf I of Germany of the Habsburg family assigned the Duchy of Austria to his sons at the Diet of Augsburg (1282), thus establishing the "Austrian hereditary lands". From that moment, the Habsburg dynasty was also known as the House of Austria. Between 1438 and 1806, with few exceptions, the Habsburg Archduke of Austria was elected Holy Roman Emperor.
The Habsburgs grew to European prominence as a result of the dynastic policy pursued by Maximilian I, Holy Roman Emperor. Maximilian I married Mary of Burgundy, thus bringing the Burgundian Netherlands into the Habsburg inheritance. Their son, Philip the Handsome, married Joanna the Mad of Spain (daughter of Ferdinand II of Aragon and Isabella of Castile). Charles V, Holy Roman Emperor (son of Philip and Joanna) inherited the Habsburg Netherlands in 1506, Habsburg Spain and its territories in 1516, and Habsburg Austria in 1519.
At this point, the Habsburg Empire was so vast that Charles V was constantly travelling throughout his dominions and therefore needed deputies and regents, such as Isabella of Portugal in Spain and Margaret of Austria in the Low Countries, to govern his various realms. At the Diet of Worms in 1521, Emperor Charles V came to terms with his younger brother Ferdinand. According to the Habsburg compact of Worms (1521), confirmed a year later in Brussels, Ferdinand was made Archduke as a regent of Charles V in the Austrian hereditary lands.
Following the death of Louis II of Hungary and Bohemia in the Battle of Mohács against the Turks, Archduke Ferdinand (who was his brother-in-law by virtue of an adoption treaty signed by Maximilian and Louis at the First Congress of Vienna) was also elected the next King of Bohemia and Hungary in 1526. Bohemia and Hungary became hereditary Habsburg domains only in the 17th century: Following victory in the Battle of White Mountain (1620) over the Bohemian rebels, Ferdinand II promulgated a Renewed Constitution (1627) that established hereditary succession over Bohemoa; and following the Battle of Mohács (1687), in which Leopold I reconquered almost all of Hungary from the Ottoman Turks, the emperor held a diet in Pressburg to establish hereditary succession in the Hungarian kingdom.
Charles V divided the House in 1556 by ceding Austria along with the Imperial crown to Ferdinand (as decided at the Imperial election, 1531) and the Spanish empire to his son Philip. The Spanish branch (which also held the Netherlands, the Kingdom of Portugal between 1580 and 1640, and the Mezzogiorno of Italy) went extinct in 1700. The Austrian branch (which also ruled the Holy Roman Empire, Hungary and Bohemia) was itself divided between different branches of the family from 1564 until 1665, but thereafter it remained a single personal union.