Name
- Maximilian I, Elector of Bavaria1
- May, Humphrey, Chancellor of the Duchy of Lancaster and Clerk to the Star Chamber1
- Mayence, Archbishops Electors of. John Suicard1
- Medici, Cosimo de', Duke of Florence, 1519-15741
- Melville, James1
- Melville, Robert, of Add MS 358311
- Mendoza, Juan, Marquis de la Ynojosa1
- Meso, Marcos, correspondent of Francisco Delgado, fl 15581
- Mewtas, Peter1
- Mexia, Francisco, diplomat and ecclesiastical writer, fl 1545-15661
- Mildmay, Henry, of Add MS 347691
- Mildmay, Walter, of Add MS 358311
- Montagu, Henry, Earl of Manchester1
- Montgomery, Charlotte1
- Montmorency, Anne, Duc de Montmorency, Constable of France1
- Morone, Giovanni, Cardinal; of Add MS 358311
- Morton, Albertus, Secretary of State1
- Munck, Levinus, Clerk of the Signet1
- Murad IV, of Turkey1
- Murray, John, 1st Earl of Annandale 16241