What drove Sir Thomas Phillipps in his pursuit of the biggest private collection of manuscripts ever assembled? Like many fanatical collectors, he seems to have found it hard to explain his obsession. But one important motive was undoubtedly to save ancient manuscripts from destruction.
In an unpublished draft (c.1828) for the preface to his catalogue of his collection, he wrote:
I was instigated by reading various accounts of the destruction of valuable MSS… My chief desire for preserving Vellum MSS. arose from witnessing the unceasing destruction of them by Goldbeaters; My search for charters or deeds by their destruction in the shops of Glue-makers and Taylors. 
A fascinating example of this is a set of Spanish naval documents now in the National Maritime Museum at Greenwich. They form part of four large collections of naval papers sold to the Museum in 1946 by the Robinson brothers, who had recently purchased the “residue” of the Phillipps manuscripts from the Trustees. The Maritime Museum paid a total of £22,000 for this remarkable set of documents, which include papers relating to Samuel Pepys, Sir Robert Cotton, Admiral Benbow and Lord Nelson, amongst others. 
The Spanish documents are described as “a large vellum-bound volume of Spanish diplomatic papers, mainly dating between 1603 and 1672, but with a section dealing with the Armada, 1587 to 1588”. They were probably once owned by the Irish antiquarian and collector Lord Kingsborough (1795-1837). His great work, The Antiquities of Mexico, contained facsimiles of various Mesoamerican codices, and was intended to demonstrate that the indigenous peoples of Mexico were descended from one of the Lost Tribes of Israel. Kingsborough’s manuscripts were offered for sale in Dublin on 1 November 1842, by the bookseller Charles Sharpe. While Phillipps himself did not buy at this sale, he subsequently acquired a number of the Kingsborough manuscripts from other sources, including booksellers like Thomas Rodd.
Phillipps may also have acquired some manuscripts from the London bookseller Obadiah Rich (1783-1850). Rich was the American Consul at Port Mahon in Menorca, and supplied various Spanish manuscripts to Kingsborough. In a letter to Phillipps, dated 20 November 1843, Rich gives a vivid description of his experiences in acquiring old documents in Madrid:
“More MSS. are destroyed by ignorant people, than by civil wars. – I once found a bookseller at Madrid occupied in taking off the parchment covers from a large pile of old folios and throwing the inside into his cellar to sell by weight to the grocers: I opened one, and immediately bought the whole (120 volumes) at about 2s. per vol: you will hardly believe that among them was one of the most precious volumes in your collection relating to England of the time of Philip the second!”
He is almost certainly referring to the volume of Spanish documents now in the National Maritime Museum (formerly Phillipps 25342). This volume actually includes the instructions given by Philip II of Spain to the Duke of Medina Sidonia, the commander of the Spanish Armada – in the King’s own handwriting.
It’s sobering to think that these documents nearly ended their days as wrapping for someone’s groceries in 19th-century Madrid! Instead, through the persistence of collectors like Kingsborough and Phillipps (and their agents like Rich), these unique papers have survived to bear witness to the events of their time.
 Phillipps, Sir Thomas, The Phillipps Manuscripts: Catalogus Librorum Manuscriptorum in Bibliotheca D. Thomae Phillipps, Bt., facsim. ed. (S.l.: Orskey-Johnson, 2001), quoted in the Introduction by A.N.L. Munby, p. 
 A.N.L. Munby, Phillipps Studies (Cambridge, 1951-60), vol. IV, pp. 13-14