The Battle of Nördlingen (Spanish: Batalla de Nördlingen; German: Schlacht bei Nördlingen; Swedish: Slaget vid Nördlingen) was fought on 27 August (Julian calendar) or 6 September (Gregorian calendar), 1634 during the Thirty Years' War. The Roman Catholic Imperial army, bolstered by 18,000 Spanish and Italian soldiers, won a crushing victory over the combined Protestant armies of Sweden and their German-Protestant allies (Heilbronn Alliance).