Former Owner
- Marienstiftsgymnasium1
- Marino Grimani1
- Mario Maffei1
- Marion Lawrence1
- Mark Lansburgh1
- Martin Schøyen1
- Marvin-L. Colker1
- Mary Elizabeth Holte1
- Mary Lusher1
- Mary, Queen of Scots1
- Matteo Barresi1
- Matthew Bloxam1
- Matthew Simpson Parkhurst1
- Matthias Corvinus1
- Maurice Johnson1
- Maurice Kann1
- Mercantile Library Company1
- Michael Tomkinson1
- Michael Wodhull1
- Michaeliskonvent1