[3] He became count of Savoy in 1391 after his father's death on 2 November 1391, caused (it was said) by poisoning, or at least bad treatment at the hands of his physicians.

This set off a struggle at the court between the grandmother and the mother, eventually involving the dukes of Berry, Bourbon, Orléans, and King Charles VI of France.

[1] The Count's early rule saw the centralization of power and the territorial expansion of the Savoyard state,[1] and in 1416 Amadeus was elevated by Emperor Sigismund to duke of Savoy.

Amadeus was sympathetic to conciliarism, the movement to have the Church managed by Ecumenical councils, and to prelates like Cardinal Aleman of Arles, who wanted to set limits upon the doctrine of papal supremacy.

[12] The president of the Council, Cardinal Louis Aleman, the archbishop of Arles, reminded the members that they needed to elect a rich and powerful pope to defend it from its adversaries.

It would eventually lead to the foundation of the University of Basel in 1460, by Pope Pius II (Piccolomini) in the bull "Inter Ceteras" of 12 November 1459.

On the same day, the pope's son, Duke Louis of Savoy, ordered the episcopal chateau of Thie to be put into the control of the cathedral Chapter of Geneva.

The Council therefore moved its sessions to the city of Lausanne, where they held their first meeting on 25 July 1448, presided over by Pope Felix V.[24] His reputation is marred by the account of him as a pontiff concerned with money, to avoid disadvantaging his heirs, found in the Commentaries of Pius II.

[25] In its fourth session, on 19 April 1449, since the throne of Peter was vacant, the Council of Lausanne elected Nicholas V as its pope.

[28] On 23 April 1449 he was appointed suburbicarian Bishop of Sabina,[29] and papal legate and Vicar Apostolic in all of the territories in the domain of the Duke of Savoy, and in the diocese of Lausanne.

[33] Pope Nicholas V wrote an apostolic brief, dated 30 April 1451, in appreciation of the life and career of Cardinal Amadeus.