Thirty Years War. The war, from 1618 to 1648, was primarily a conflict between the Habsburgs and their Spanish allies against France, Sweden, and the Dutch. There were two reasons why England might be drawn into it. The casus belli was the decision by the Bohemians to defy the Habsburgs and offer their throne to Frederick of the Palatinate, who was married to Elizabeth, daughter of James I. Secondly, there was a religious element to the war which, despite France's opposition to the Habsburgs, was seen by many protestants as a catholic crusade. England took little part in the conflict and for the last ten years was preoccupied with her own troubles. James resisted pressure to intervene, partly because Parliament's enthusiasm for war was not matched by enthusiasm for supply, partly because he was seeking a Spanish marriage for his son Charles. After the breakdown of the negotiations, Charles demanded war with Spain: the expedition of 1625 was a fiasco. He then compounded his difficulties by becoming involved in war with France as well, a masterpiece of incompetence, which meant that he was now fighting both sides. The expedition in 1627 to relieve La Rochelle was no more successful than that of 1625. Luckily, Charles's relations with Parliament were so bad that he was obliged to make peace with both countries and leave them to fight it out without English assistance. The conflict was concluded by the treaty of Westphalia in 1648, by which time Charles was a prisoner awaiting trial.

J. A. Cannon