1936
National Gallery of Art, 1500
National Gallery of Art, 1904
National Gallery of Art, 1570
United States Government, 1936
National Gallery of Art, 1935
National Gallery of Art, 1936
United States Government, 1937
National Gallery of Art, 1940
National Gallery of Art, 1741
National Gallery of Art, 1490
![The Mass of Saint Gregory [recto]](https://api.nga.gov/iiif/4d23fcb3-6c20-4387-b54f-a89d717bd134/full/843,/0/default.jpg)
