House of Habsburg
 Leopoldian split and Imperial elections

Rudolf IV 's brothers Albert III and Leopold III ignored his efforts to preserve the integrity of the family domains and enacted the separation of the so-called Albertinian and Leopoldian family lines on 25 September 1379 by the Treaty of Neuberg. The former would maintain Austria proper (then called Niederösterreich but comprising modern Lower Austria and most of Upper Austria), while the latter would rule over lands then labeled Oberösterreich, namely Inner Austria (Innerösterreich) comprising Styria, Carinthia and Carniola, and Further Austria (Vorderösterreich) consisting of Tyrol and the western Habsburg lands in Alsace and Swabia.

By marrying Elisabeth of Luxembourg, the daughter of Emperor Sigismund, in 1437 Duke Albert V of the Albertine line (1397–1439) became the ruler of Bohemia and Hungary, again expanding the family's political horizons. The next year Albert was crowned King of the Romans, known as such as Albert II. Following his early death in a battle against the Ottomans in 1439 and that of his son Ladislaus Postumus in 1457, the Habsburgs lost Bohemia once more as well as Hungary for several decades. However, with the extinction of the House of Celje in 1456 and the House of Wallsee-Enns in 1466/1483, they managed to absorb significant secular enclaves into their territories and create a contiguous domain stretching from the border with Bohemia to the Adriatic Sea.

After the death of Leopold's eldest son, William, in 1406 the Leopoldian line was further split among his brothers into the Inner Austrian territory under Ernest the Iron and a Tyrolean/Further Austrian line under Frederick of the Empty Pockets. In 1440 Ernest's son Frederick III was chosen by the electoral college to succeed Albert II as the king. Several Habsburg kings had attempted to gain the imperial dignity over the years, but success finally arrived on 19 March 1452, when Pope Nicholas V crowned Frederick III as the Holy Roman Emperor in a grand ceremony held in Rome. In Frederick III the Pope found an important political ally with whose help he was able to counter the conciliar movement.

While in Rome Frederick III married Eleanor of Portugal, enabling him to build a network of connections with dynasties in the west and southeast of Europe. Frederick was rather distant to his family; Eleanor, by contrast, had a great influence on the raising and education of Frederick's children and therefore played an important role in the family's rise to prominence. After Frederick III's coronation the Habsburgs were able to hold the imperial throne almost continuously until 1806.
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