He had several interviews with Catherine de' Medici in Paris, offering to help make Henry III of France king of Ireland, and was granted a pension of 5,000 crowns in 1576. Early in the following year he left for the Spanish court, where he offered the crown to the brother of King Philip II, Don John; the king was cautious, however. FitzMaurice left his sons Maurice and Gerald with Cardinal Granvelle, and travelled to Italy to meet Pope Gregory XIII. At the papal court FitzMaurice met adventurer Captain Thomas Stukley, and together they persuaded the pope to underwrite the cost of 1,000 troops to invade Ireland, most of whom, according to O'Sullivan Beare, were desperadoes the pope wished to get out of Italy. Fitzmaurice and Stukley were to rendezvous in Lisbon and proceed to Ireland, however, Stukley decided to throw his troops and support to King Sebastian's expedition to Morocco, where he died. Following the diversion of Stukley to Morocco, FitzMaurice set out with the nuncio, Nicholas Sanders, and Matthew de Oviedo from Ferrol in Galicia, Spain on 17 June 1579 with a few troops on his vessel and three Spanish shallops; they captured two English vessels in the channel and arrived at Dingle on 16 July 1579, launching the Second Desmond Rebellion. On the 18th they cast anchor in Smerwick, where they garrisoned at Dún an Óir (Fort of Gold), and were joined on the 25th by two galleys with 100 troops; four days later their ships were captured by the English fleet under the command of Sir William Winter. Having exhorted the Earl of Desmond and the Earl of Kildare, as Geraldine leaders, to fight the heretics, FitzMaurice left the fort to await the arrival of Stukley (who, unknown to him, had been killed at the Battle of Alcácer Quibir in the previous year, during a campaign by King Sebastian of Portugal). FitzMaurice went to make a vow at the monastery of the Holy Cross in Tipperary but became caught in a skirmish with the forces of his cousin, Theobald Burke, during which he was shot with a ball in the hollow of the chest, but cut his way through to Burke and his brother William, both of whom he killed with single strokes of his sword. The battle was won, but close to the scene his injuries overcame him; he made his will and ordered his friends to cut off his head after death in order that his enemies might not mutilate his body; he begged his attendants to attest that he had not turned tail on the enemy.