This started re-Catholisation of the Czech lands, but also expanded the scope of the Thirty Years' War by drawing Denmark and Sweden into it.

[1] Some of the Protestant leaders of Bohemia feared they would be losing the religious rights granted to them by Emperor Rudolf II in his Letter of Majesty (1609).

However, other Protestants supported the stance taken by the Catholics, and in 1617, Ferdinand was duly elected by the Bohemian Estates to become the crown prince, and automatically upon the death of Matthias, the next King of Bohemia.

The king-elect then sent two Catholic councillors (Vilem Slavata of Chlum and Jaroslav Bořita of Martinice) as his representatives to Prague Castle in May 1618.

On 23 May, an assembly of Protestants seized them and threw them (and also secretary Filip Fabricius) out of the palace window, which was some 17 metres (56 ft) off the ground.

However, similar offers were made by other members of the Bohemian Estates to the Duke of Savoy, the Elector of Saxony, and the Prince of Transylvania.

Oñate conspired to transfer the electoral title from the Palatinate to the duke of Bavaria in exchange for his support and that of the Catholic League.

As the rebellion collapsed, the widespread confiscation of property and suppression of the Bohemian nobility ensured the country would return to the Catholic side after more than two centuries of Hussite and other religious dissent.

This would have the effect of bringing in elements of the Protestant Union which had suffered a severe blow to their credibility via their refusal to support the Bohemian revolutionaries.

In addition, the changes in territory meant that previously unaligned powers would find a resurgent empire on their own borders, a circumstance that kingdoms like Denmark found untenable.