Former Owner
- Martin Picker2
- Martin Schøyen2
- Martin of Aragon1
- Marvin-L. Colker1
- Mary W. T. Dickinson1
- Matteo Luigi Canonici2
- Mayer Sulzberger2
- Maḥmūd bin Nāṣir1
- Melk Abbey2
- Meschatin La Faye family1
- Michael Greenberg1
- Mikhail Golitsyn1
- Milton Fischmann8
- Mirmellus Arnandi1
- Monasterio de El Paular1
- Monastery of Saint Peter (Erfurt, Germany)1
- Moor of Ireton1
- Mount Zion Abbey1
- Mrs. F. W. Bartlett1
- Muḥammad Nāṣir al-Dawlah1