12. How long did the Thirty Years War last?
Lasting from 1618 to 1648, the conflict started along religious sectarian lines within the German states, but shifting alliances gradually embroiled all of western Europe. The war fell into four phases: the Palatine-Bohemian (1618-1625), the Danish (1625-1629), the Swedish (1630-1635), and the French (1635-1648).
