Staunch supporters of the Emperors against the papacy, they reached the height of their power in the aftermath of the battle of Marchfeld between the 1280s and 1310s, when they controlled most of contemporary Slovenia, western and south-western Austria and part of northeast Italy mostly as (princely) Counts of Gorizia and Tyrol, Landgraves of Savinja and Dukes of Carinthia and Carniola.

In 1286, the Gorizia-Tyrol line became Dukes of Carinthia and landraves of Carniola, and took over de facto rule in Savinja, while the Albertine branch was granted most of the Windic March and the County of Metlika.

Tyrol already in the early and later Middle Ages was an important mountain pass area with the lowest crossings over the Central Eastern Alps, vital for the Holy Roman Emperors to reach the Kingdom of Italy.

The centres of the Imperial power were initially two Prince-bishoprics established by Emperor Conrad II in 1027, Brixen (Bressanone) and Trient (Trento).

The bishops were the sovereigns of many semi-free compulsory henchmen (ministeriales) and local noblemen which styled until today the scenery with their numerous castles mostly south of the Brenner Pass.

As Henry himself left no male heirs upon his death in 1335, the Austrian House of Habsburg inherited Carinthia and Carniola from the Gorizia-Tyrol branch.

During his later reign his administrator Virgil von Graben was persuaded by grand promises by King Maximilian I to end his hitherto secret association with the Venetians and instead advocate the country's accession to the Habsburg Empire.

[1] The enlightened views of the Republic of Venice and its decision-makers would have recognized the Gorizian (Meinhardin) bastard Von Graben himself as the new Count of Gorizia.

However, since Virgil von Graben ended the contract with Venice about the succession in the County of Gorizia and negotiated with Maximilian I, this appointment did not materialize.

After the death of Leonhard on 12 April 1500 and the Gorizia inheritance in favor of the Habsburgs, the Venetians saw their failure solely in the actions of the lords Virgil and Lukas von Graben.

[5] Upon his death, Austrian troops immediately occupied the town of Gorizia and Virgil vin Graben became his successor as imperial stadtholder of Lienz in East Tyrol.