The papers of Edward Montagu, the first Earl, consist of five volumes containing papers relating to his political career 1656-1669.

The papers of John Montagu, fourth Earl of Sandwich, consist of five volumes of appointment books, 1771 to 1782, purchased from the Montagu family in 1957 and transcripts. In 1956 and 1960 the Secretary of the Navy Records Society deposited on loan transcripts of Sandwich's papers, 1771 to 1782, not included in the Society's publication. The Heritage Lottery Fund has supported the purchase of additions to this collection.

Administrative / biographical background
Edward Montagu, first earl of Sandwich, KG (1625–1672), army and naval officer and diplomat, was born at Barnwell, Northamptonshire, on 27 July 1625, the second but eldest surviving son of Sir Sydney Montagu (circa 1571–1644) of Hinchingbrooke, Huntingdonshire. Montagu was MP for Huntingdonshire and groom of the bedchamber to James I. In October 1655 he was appointed to the admiralty committee and later general at sea (2 January 1656). This was a position he shared with Robert Blake whose illness led to Cromwell’s need for another trusted authority in the fleet, thus securing Montagu’s elevation. The fleet under Montagu and Blake sailed on 15 March 1656 and took command in the first-rate NASEBY. Successfully reconnoitring Tangier, Tetuan and Gibraltar the NASEBY returned home and on 17 July Montagu commanded the fleet to support the attacks on Dunkirk and Mardyke. In 1659 Montagu took command of a fleet set for the Baltic, finding forces of Charles X of Sweden at Copenhagen and redirecting his efforts to persuade the Dutch to remain peaceful and not intervene. However Montagu withdrew upon hearing the fall of Richard Cromwell. He was appointed to the council of state on 23 February and made general at sea jointly with Monck on 2 March 1660; appointed to the admiralty commission on 3 March. Montagu’s critical involvement in the landing of the Royal party at Dover on 25 May 1660 led to his being made an earl, choosing Sandwich for his title on 12 July 1660, later a knight of the Garter. In the Second Anglo-Dutch War 1665-1667 he fought at the Battle of Lowestoft and later defeated at the Battle of Vagen. He was re-appointed in 1672 at the start of the Third Anglo-Dutch War he was appointed Vice- Admiral of the Blue serving in the ROYAL JAMES. He was killed at the Battle of Solebay, his ship destroyed by a group of fire ships. He was laid to rest at Westminster Abbey on 3 July 1672 after a state funeral beginning along the River Thames as part of decorated barges sailing from Deptford. Interestingly, Montagu was the first cousin of the father of Samuel Pepys. John Montagu took his seat in the House of Lords in 1739 and in 1744 was appointed one of the Lords of the Admiralty. He represented the United Kingdom at the negotiations leading to the conclusion of peace in 1748. He then became First Lord of the Admiralty 1748 to 1761, for a brief period in 1763 and again from 1771 to 1782, after which he held no further public office. A selection of his papers were published by Sir George Barnes and Commander J.H. Owen, 'The private papers of John, Earl of Sandwich 1771-1782' (Navy Records Society, 1932-1938, 4 volumes). There is a biography by George Martelli, 'Jemmy Twitcher, a life of the Fourth Earl of Sandwich' (London, 1962).