The Siege of Rheinfelden of 1633 or the Spanish recapture of Rheinfelden (Spanish: La Expugnación de Rheinfelden) took place in late October 1633, during the Thirty Years' War. The Spanish army (20,000 troops) of the Governor of the Duchy of Milan, Don Gómez Suárez de Figueroa, Duke of Feria, (Spanish Army of Alsace), after relieving and taking Konstanz, Breisach and Bregenz, captured by storm the Swiss city of Rheinfelden, as part of the plan designed by the favourite and chief minister of Philip IV of Spain, Don Gaspar de Guzmán, Count-Duke of Olivares, to release the Rhine route of the harassment by Swedish, French and Protestant-German troops (Heilbronn League), defend the Franche-Comté, safeguard the Tyrol, support the troops of the Holy Roman Empire, and open a strategic corridor for