Power struggles between Kings of France and Habsburg rulers of Holy Roman Empire and Spain.
War fuelled by conflict between Calvinism and Catholicism, and also by the underlying constitutional conflict between Holy Roman Emperor and the German Princes. Spain collapsed and left the emperor isolated. Peace negotiations opened and ended German war at the Peace of Westphalia. I's unpopular policies towards the Scottish kirk. Resulted in English defeats and bankruptcy for Charles who was then forced to call the Short and Long Parliaments in 1640, bringing to an end his personal rule.