He was successively bishop of Maguelonne (1418), archbishop of Arles (1423) and cardinal priest of St Cecilia (1426). He was a prominent member of the council of Basel, and, together with Cardinal Julian Cesarini, led the party which maintained the supremacy of general councils over the pope's authority.
In 1440 Aleman obtained the support of the emperor Sigismund and of the duke of Milan to his views, and proclaiming the deposition of Pope Eugenius IV, placed the tiara upon the head of Amadeus VIII, duke of Savoy (henceforward known as antipope Felix V).
Eugenius retorted by excommunicating the antipope and depriving Aleman of all his ecclesiastical dignities. In order to make an end of the schism, Felix V finally abdicated on Aleman's advice, and Nicholas V, who had succeeded in 1447, restored the cardinal to all his honours and employed him as legate to Germany in 1449.
On his return he retired to his diocese of Arles, where he devoted himself zealously to the instruction of his people. He died on September 16 1450, and was beatified by Pope Clement VII in 1527.
See U. Chevalier, Repert. des sources hist. (Paris, 1905), p. 130.
Initial text from 1911 encyclopedia -- Please update as needed.