Habsburg Claim to the Hungarian Throne

Timeline

1. 1526Pressburg · SlovakiaThe western Hungarian nobility convened a diet at Pressburg and, invoking the marriage succession clauses of the 1515 Treaty of Vienna, elected Archduke Ferdinand of Austria king of Hungary to counter the Zápolya faction.
2. 1527Western Hungary · HungaryFerdinand sent Habsburg forces into western Hungary, gradually seizing key towns such as Pest and Buda and engaging Zápolya's forces militarily. Western nobles and Austrian reinforcements became the core of Ferdinand's camp.
3. 1527Székesfehérvár · HungaryFerdinand was formally crowned king of Hungary at Székesfehérvár, creating a dual-kingdom situation alongside Zápolya. The Habsburgs thereby brought Hungary into the imperial sphere, facing the Ottoman eastward expansion threat directly.