![A head-and-shoulder portrait of the Duke of Mercoeur, face turned slightly to the left, in an oval border which reads: Philip : [etching] Crédit : Bibliothèque nationale de France, département Estampes et photographie, RESERVE FOL-QB-201 (13)](/becedia/sites/default/files/medias/dossiers-thematiques/la-republique-de-saint-malo/mercoeur.JPEG "A head-and-shoulder portrait of the Duke of Mercoeur, face turned slightly to the left, in an oval border which reads: Philip : [etching] Crédit : Bibliothèque nationale de France, département Estampes et photographie, RESERVE FOL-QB-201 (13)")
Born into nobility, Phillippe-Emmanuel of Lorraine owed his rise to power to the protection of Henry III, who married his sister, Louise of Lorraine. The king favoured his marriage to Marie of Luxemburg, heiress to the rich appanage of the Penthièvre and consequently descendent of the Dukes of Brittany. Moreover, her father was the governor of Brittany between 1562 and 1569. Henry III accorded him the government of Brittany in 1582 when he was only 24 years old because he was hoping to be able to rely upon a loyal ally in Brittany during the troubling times of civil war.
But Mercoeur was equally a cousin of the Guises, the youngest branch of the Lorraine family and organisers of the Catholic League. The assassination of the Duke of Guise and his brother the Cardinal of Lorraine under the orders of Henry III on December 23rd 1588, led Mercoeur to gradually join the opposing side namely the Catholic League and in turn make Brittany enter the civil war. Indeed in general, Brittany followed its governor and joined the Catholic League camp, with a few noteworthy exceptions, such as Rennes, Vitré and Brest.
Mercoeur was dismissed from his post as governor of Brittany in April 1589, but the king had lost the province and Mercoeur continued to consider himself as the legitimate governor. He therefore established an autonomous Breton administration in Nantes in opposition to that of the King. He established a veritable government council, summoned the States of Brittany and founded a Parliament. He allied himself to Philip of Spain and through this he gained the military support of 7 000 men as well as large subsidies. With Spanish aid, he defeated Henry IV’s army in May 1592, in Craon, in the Maine.
After the conversion of Henry IV to Catholicism in 1593, he found himself increasingly isolated however. He finally submitted to Henry IV with a treaty signed at Angers on the 20 March 1598. He gave up the government of Brittany in exchange for over four million pounds, a staggering amount, and gave up the marriage of his daughter to César of Bourbon, Duke of Vendôme, the illegitimate son of Henry IV who in turn became governor of Brittany. Mercoeur left Brittany ruined after almost ten years of civil war and went to Hungary to fight the Turks. He died in Nuremburg in 1602.