Interior view of the Chapel of St Peter Martyr (also known as the Portinari Chapel) at the Basillica of Sant'Eustorgio, Milan. Internally the chapel has architectural features that bear similarity to Brunelleschi's Old Sacristy at San Lorenzo and is articulated with a system of pilasters and arches, in places richly decorated with formal motifs. Between the arches can be seen three of the four frescoed pendentives by Vincenzo Foppa of the Four Doctors of the Church. The remainder of Foppa's frescoes remain hidden (they were not rediscovered until 1878), except for a small fragment to the left of the right-hand window.