Sardinia, sahr DIHN ee uh, Kingdom of, became the nucleus of united Italy. The kingdom was founded in 1720 when the Duchy of Savoy, a territory in northwest Italy, was joined with the island of Sardinia. The kingdom included the Piedmont region, around which the Duchy of Savoy was centered. As a result, the kingdom is also known as Piedmont-Sardinia. Victor Amadeus II of Savoy became the first monarch of the Kingdom of Sardinia.