alternatehistory.com

On 1544, John Sigismund, the son of Isabella Jagiellon and John Zapolya would die, forcing Isabella Jagiellon to marry Archduke of Ferdinand of Austria on 1546 who would be given the Duchy of Opole-Raciborz, starting the Opole line of the Habsburgs as the marriage have resulted in the birth of two sons; Ferdinand(June 3, 1547) and Maximilian (June 4, 1553).