Source: National Gallery Prague, public domain
On April 9, 1624 Ferdinand II issued a patent allowing only the Catholic religion in Bohemia. A few days later he banned royal towns from accepting non-Catholic burghers and also forbade non-Catholics to practice their trade in such towns.
The Battle of White Mountain in 1620 was fatal for the Protestant Estates. With the victory of the imperial troops, a new phase of re-Catholization began under Emperor Ferdinand II.
Re-Catholization took basically two forms: a strict, harsh and uncompromising approach using all means of coercion; and a gradual, consistent and non-violent approach with an attempt to awaken a genuine and sincere interest in the Catholic faith. Any rebellion was nipped in the bud.
See the rest here.