On being created cardinal by Innocent VII. he devoted all his energies from 1408 onwards to the realization of the union of the church, in spite of the two rival popes. He was one of the promoters of the council of Pisa, and after that assembly had declared Gregory XII. and Benedict XIII deposed, the cardinals assembled in conclave thought they could not do better than crown with the tiara this cosmopolitan prelate, who had an equal mastery of the Latin and Greek languages, and was renowned not only for his learning in theology but for his affability (June 26, 1409). As a matter of fact, the only effect of this election was to aggravate the schism by adding a third to the number of rival pontiffs.
During his short reign of ten months Alexander V.'s aim was to extend his obedience with the assistance of France, and, notably, of the duke Louis II. of Anjou, upon whom he conferred the investiture of the kingdom of Sicily, together with the title of gonfalonier of the church. He proclaimed and promised rather than effected a certain number of reforms: the abandonment of the rights of "spoils" and "procurations," the re-establishment of the system of canonical election in the cathedral churches and principal monasteries, etc.
Death came upon him almost without warning at Bologna, in the night of the 3rd-4th May 1410. A rumour went about that he had been poisoned by the cardinal Baldassare Cossa, impatient to be his successor, who succeeded him in fact under the name of John XXIII. The crime has, however, never been proved, though a Milanese physician, who performed the task of dissecting the corpse of Peter Philarges, seems to have thought that he found traces of poison. (N. V.)