How did the Habsburg marriage agreements with the Jagiellon dynasty strengthen claims to Bohemia and Hungary?

The Habsburg marriage agreements with the Jagiellon dynasty were a strategic diplomatic effort to secure hereditary succession rights in Bohemia and Hungary.12

In 1515, Maximilian I arranged a double marriage between his family and the Jagiellon line, which formally revived earlier Habsburg claims to these kingdoms. These agreements were designed to ensure that if the Jagiellonians died out, the crowns of Bohemia and Hungary would pass to the Habsburgs.123

The effectiveness of this policy was realized following the Battle of Mohács in 1526, where the Jagiellon king Louis II was killed. Because Ferdinand I—who had married Louis II’s sister, Anna, in 1521—could invoke the succession rights established by the 1515 accords, he was able to stand as a candidate for the vacant thrones. Ferdinand was subsequently elected king of Bohemia, though his claim to Hungary faced significant opposition and led to a prolonged conflict.4516