Demonia (1990)

In southeast Sicily, a team of archaeologists investigate the ruins of a crypt where heretic nuns had been stoned and crucified by the village people in the 16th century. Soon strange things begin to happen, and Liza, one of the team members, starts to have surreal dreams about the nuns. Then the graphic violence begins, starting with a decapitation! The answers lie in the ancient crypt of the nuns.