Former Owner
- McCormick Theological Seminary1
- Melk Abbey1
- Michael Tomkinson1
- Michaeliskonvent1
- Michel Chasles1
- Michele Amari1
- Miguel de Mayora1
- Millard Meiss1
- Milt Freudenheim1
- Moissac Abbey1
- Monasterio de El Paular1
- Monastery at San Gregorio al Celio1
- Moritz Dessauer1
- Moritz Joseph Johann von Dietrichstein1
- Morris H. Morgan1
- Mortimer Frank1
- Morton Parker Eden1
- Muriel Agnes Fry1
- Murray Anthony Potter1
- Mushtaq Ali Khan I of Rampur1