Frederick Hermann, first Duke of Schomberg, first Earl of Mértola, member of the Garter Order (the highest order of chivalry across the United Kingdom), Marshal of France and General of both the English and the Portuguese Army, died at the Battle of Boyne (between England and the Netherlands) in 1690.
After the signing of the Treaty of the Pyrenees (signed to end a conflict between France and Spain, which at the time was part of the Thirty Years War), the independence of Portugal was threatened by Spain. At this point Frederick
Schomberg was secretly sent to Lisbon, with the approval of King Charles II of England, to serve as a military adviser. To avoid problems with Spain (regarding the treaty of the Pyrenees), King Louis XIV of France waived Schomberg of his obligations to the French army.
After several adversities in the first three military campaigns, in June 17 of 1665, the Commander Portuguese António de Sousa (the first Marquis of Marialva) together with General Frederick von Schomberg, won the Battle of Montes Claros, the last step in the Portuguese Restoration War, contributing to the full sovereignty of Portugal.
After participating with his army in the overthrowing of King Alfonso VI of Portugal, on behalf of his brother Dom Pedro, he was rewarded with the Earl of Mértola title and a lifetime annual pension.