Rudolf had decreed the joint rule of his younger brothers by house law (Rudolfinische Hausordnung) in 1364. However, they fell out with each other soon after his death. On 9 September 1379 a partition treaty was signed in Neuberg Abbey in Styria:
Leopold and his descendants (Leopoldian line) became the exclusive ruler of Styria (then including Pitten and the town of Wiener Neustadt), Carinthia, Carniola (enlarged by the Windic march and territory in the March of Istria since 1374), Tyrol and Further Austria, as well as Trieste and acquisitions in Friuli (the latter were annexed to Carniola).[2]
Regardless of their territories, all Habsburg rulers would retain the Austrian archducal title.
Aftermath
Under Leopold's sons, the Leopoldian possessions were further subdivided into Inner Austria (i.e. Styria, Carinthia, Carniola, and Littoral) and 'Upper Austria' (not to be confused with the present-day Austrian federal state), comprising Tyrol and the Further Austrian lands, from 1406 ruled by Leopold's youngest son Duke Frederick IV.
The split between the Albertinian and Leopoldinian lines of the Habsburg family and the Austrian lands enfeebled the dynasty's position. The Albertinian archduke Albert V of Austria was elected King of the Romans in 1438. Nevertheless, he died one year later and the line finally became extinct by the death of his son Ladislaus the Posthumous in 1457. The territories were inherited by the Leopoldian archduke Frederick V of Inner Austria, Albert's successor as King of the Romans and from 1452 also Holy Roman Emperor. Finally, in 1490, all Habsburg territories were reunified, when Archduke Sigismund handed over the rulership of Tyrol and Further Austria ('Upper Austria') to Emperor Frederick's son King Maximilian I.