Treaty of Brussels (1656)

The Treaty of Brussels was an agreement between representatives of Philip IV of Spain and Charles II the leader of the exiled Royalists of England, Ireland and Scotland. It was signed in Brussels in the Spanish Netherlands on 2 April 1656. It was signed on Charles' behalf by the Earl of Rochester and the Irish leader Ormonde. Alonso de Cárdenas, a former Spanish Ambassador to London, signed on behalf of his King.

The exiled Royalists had previously been close to the French court, but following the 1655 alliance agreed between the English Commonwealth and the French government they were driven into the arms of France's enemy Spain. In exchange for potential future Spanish military support to regain his throne, Charles agreed to raise forces to fight for Spain in the ongoing war against France. He also pledged to stop English colonisation in the Americas and return any territory taken in future by the English Republic from Spain. He also agreed to help resist Portugal's war to gain its independence from Madrid.

The following year the English Republic signed the Treaty of Paris with France, formalising the developing Anglo-French alliance.

His alliance with the nation's traditional enemy Spain, further undermined Charles' support with the English public. Nonetheless, Royalist supporters joined the Spanish army in large numbers led by Charles' younger brother James, Duke of York. Large numbers of Irish troops deserted the French army to serve under York, leading to hopes that they could invade England. These hopes were largely dashed by the Spanish defeat to Anglo-French forces at the Battle of the Dunes in 1658. Spain made peace with France at the Treaty of the Pyrenees in 1659, and even the death of Oliver Cromwell did not lead to the immediate collapse of the English Republic.

...
Wikipedia