He was a significant medieval ruler who played a crucial role in the expansion and consolidation of the House of Savoy’s influence in the regions that are now part of modern-day France, Italy, and Switzerland.

[1] Following his marriage to Sybille of Bâgé in 1272, Amadeus began life in the service of his cousin, King Edward I of England, as a household knight, serving in the First Welsh War of 1277.

During the Second Welsh War of 1282, he was in command of Edward's forces at Chester that relieved the siege of Rhuddlan Castle.

He pursued an alliance with the Kingdom of France and received Maulévrier in Normandy as a result of initial good relations.

The eventual recovery of Lyon by the kings of France alerted Amadeus to their expansionistic tendencies towards the regions by the Alps.

He sought a powerful ally against potential hostility in the German king Henry VII, who was married to Margaret of Brabant, the sister-in-law of Amadeus.