Former Owner
- Monasterio de El Paular1
- Monasterium sanctorum quadraginta martyrum (Treviso Italy)1
- Monastery of Benevívere1
- Monastery of Our Lady of the Angels of Churubusco1
- Monastery of Saint Peter (Erfurt, Germany)1
- Monastery of San Bartolmeo, Arezzo, Tuscany1
- Monica Franklyn1
- Monsieur de Bel Air1
- Moor of Ireton1
- Morot1
- Morris H. Morgan5
- Morris Jastrow, Jr.1
- Mortimer Frank1
- Morton Davis Mitchell1
- Mount Zion Abbey1
- Mr. Hals1
- Mrs. E.J. Hooper1
- Mrs. F. W. Bartlett1
- Mrs. Turnbull1
- Muriel Agnes Fry1