Giaveno returned to the abbots of San Michele with a donation from the Count of Savoy Tommaso I on 21 February 1209, who fortified the square with a robust wall and built a castle there. Subsequently, in 1347, Abbot Rodolfo di Mombello decided to "villam iavenni murare", with two trebuchet walls (about 6 meters high), interspersed with five circular towers. The perimeter of the "Abbey Citadel" is still clearly legible today.