Second youngest of the sons of Claude, Duke of Guise and Antoinette de Bourbon, the Grand Prior was selected for a life with the Order of Malta.
He and his brother Elbeuf played a key role in the capture of Corse in 1553, defending the island against attempted counter attacks by the Genoese.
However, difficulty with his subordinates, government finance issues, and internal instability brought about by the Conspiracy of Amboise would lead to peace being declared in June 1560 with England, cancelling the expedition while the Grand Priors fleet was still travelling up France's west coast.
[1] Despite becoming Grand Prior, the dispensation from the Pope allowing him to hold the office without joining a Holy Order meant that it was theoretically possible for him to marry.
[5][6][7] With the death of Claude in April, it was decided that though the body would be put in a lead lined coffin, the burial would be left until June, as time was needed for Lorraine, Cardinal Guise and the Grand Prior to hurry home from Rome where they had recently observed the election of a new Pope which had taken place in February.
[8] With the resumption of the Italian Wars in 1551, the Grand Prior and Elbeuf provided support to their brother Aumale's command of the cavalry under the overall authority of Marshal Brissac.
Elbeuf and the Grand Prior hurried into the city, alongside much of the flower of the French nobility for the opportunity of glory that a successful defence presented.
Elbeuf and the Grand Prior were dispatched to offer their assistance for the campaign in late 1553, and to help rebuff any counter offensive by the Genoese Admiral Andrea Doria.
[17] After the disaster at the battle of Saint-Quentin in which the Constable was captured and the French army destroyed, Guise who was campaigning in Italy was urgently called back to France to assume military command.
[18][19] In 1558, the Grand Prior received a new office, that of general of the galleys, giving him military authority over the naval forces in the Mediterranean, this was at the expense of the baron de la Garde, who was hoping for the appointment.
However, while the Grand Prior, commander of the French galley's sat waiting in Provence, the fleet decided to take a detour, pillaging the coast of Naples in June, before burning down Ciutadella de Menorca on 12 July.
[21] With the death of Henri in 1559, Jacques de la Brosse secured his own ordinance company under the kings successor François II of France.
He had difficulty with his subordinates, such as François de Coligny d'Andelot, who refused to embark with his men, little desiring to campaign in Scotland, leading many other captains to follow his example.
[27] The meeting ended positively, however all good will was shattered several weeks later when, while returning to the capital, the duke of Guise's men committed a massacre of Protestant worshippers at Wassy.