Born in 1383 in Chambéry, Savoy. Amadeus VIII became count of Savoy at age 8 after the sudden death of his father in 1391. At the ripe old age of 10, he married Mary, daughter of Phillip the Bold, duke of Burgundy.

As a teenager, he would expand the territories of Savoy, purchasing nearby land and laying claim to Geneva.

In 1416 the Holy Roman Emperor Sigismund would elevate Savoy to a duchy, making Amadeus VIII a duke.

After the Council of Basel split with Pope Eugene IV, Amadeus would be elected an antipope in 1439. He served as Pope Felix V for 10 years before abdicating and recognizing the legitimacy of Eugene's successor, Pope Nicholas V.

The first duke of Savoy would die in Geneva in 1451.