The thirty years' war
The Thirty Years' War, which erupted in 1618 in Bohemia, reaches the Rhine in 1621. In the Protestant and Catholic regions dependent on the Emperor, there is levying of troops or payment of mercenaries who lay waste to the land. The Alsace is devastated by the troops of Mansfeld in 1621-1622, but more especially by the troops of Gustav Adolf of Sweden starting in 1632. The conflict develops into a methodical conquest of Hapsburg holdings. This conquest reaches its culmination in December 1638 with the surrender of the fortress of Breisach to the troops of Bernhard of Saxony-Weimar.