The religious wars continued after the Czech defeat. The Thirty Years' War (1618–48) of the German Protestant princes against the Holy Roman Emperor involved foreign powers and extended beyond German territory. Czechs fought on all sides: most of the rebellious Czech generals joined Protestant armies; Albrecht of Wallenstein was the most prominent Czech defector to the imperial cause. Bohemia served as a battlefield throughout the war. Prince Bethlen Gabor's Hungarian forces, reinforced by Turkish mercenaries, fought against the emperor and periodically devastated Slovakia and Moravia. Protestant German armies and, later, Danish and Swedish armies, laid waste the Czech provinces. Cities, villages, and castle fortresses were destroyed. Lusatia was incorporated into Saxony in 1635.