 Gravesano also includes the hamlet of Grumo, that was home to a medieval castle that ruled over both villages as well as Manno and Bedano.The castle, which was on the road from Ponte Tresa to Monte Ceneri Pass, was visited in 1004 by Emperor Henry II and later by Frederick Barbarossa during his Italy campaign in 1162.The monastery of San Pietro in Ciel d'Oro of Pavia and the Bishop of Como both held property and rights in Gravesano.