Devolution, War of, 1667-68, a war between France and Spain in which France conquered the Spanish Netherlands (now Belgium). Louis XIV of France began the war on the claim that ownership of the area had devolved on (passed to) his wife, Marie Thérèse, at the death of her father, Philip IV of Spain. Marie Thérèse had renounced any such inheritance in return for a dowry, but, as Louis pointed out, the dowry had never been paid.

In the War of Devolution French forces also seized Franche-Comté, a Spanish possession that bordered on Switzerland. By the Treaty of Aix-la-Chapelle, 1668, Louis returned Franche-Comté but kept part of the Spanish Netherlands, including the city of Lille.