It was originally a county but raised to a Duchy in 1416. It greatly increased in size due to the Kingdom of Sardinia being added to the Savoy family possessions. Parts of the Duchy of Milan had also been added before. The small duchy was a neighbour to the Duchy of Parma as well as the larger wealthier Grand Duchy of Tuscany both of which would later form close relationships with eachother often through marriages between princes and princesses. 