[2] In 1365, Pope Urban V selected Leo as the potential ruler of Cilician Armenia, but Constantine IV ascended the throne instead.

[3] Leo ruled until April 13, 1375 when he was overthrown and captured following the fall of Sis by an invading army from the Mamluk Sultanate in Egypt.

[citation needed] According to father Juan de Mariana, Leo left Castile for France after the death of his protector in 1390.

Leo V apparently went to Paris in June 1384, and received the Saint-Ouen castle and a sizable pension from King Charles VI of France.

[7] He attempted to reconcile the French and the English (at the time fighting the Hundred Years' War) in order to set up a new Crusade[1] and obtain help to recover his lands, but the meeting he organized in 1386 between Boulogne and Calais were unsuccessful.

His remains were laid to rest in the Couvent des Célestins, the second most important burial site for royalty after Saint-Denis, located near what is now the Place de la Bastille in Paris.