The Letter of Majesty (1609) was a 17th-century European document, reluctantly signed by the Holy Roman Emperor, Rudolf II, granting religious tolerance to both Protestant and Catholic citizens living in the estates of Bohemia. The letter also created a Bohemian Protestant State Church, run by said estates. A similar Letter was issued for Silesia.
But in 1611, Rudolf inexplicably permitted his cousin Leopold to invade Bohemia with some 7,000 troops. A considerable Bohemian force drove Leopold back from the suburbs of Prague, and the Bohemian Estates called upon Matthias to take over the government of their kingdom.
References
Letter of Majesty Wikipedia(Text) CC BY-SA