right:

Raphael
The Betrothal of the Virgin (Sposalizio), 1504
Pinacoteca Brera, Milan

left, top:

Botticelli
The Tragedy of Lucretia, 1500-1501
Isabella Stewart Gardner Museum, Boston

left, bottom:

Perugino
Christ Giving the Keys to Peter, 1481-2
Sistine Chapel, north wall