Previous owners:
- George Suttie, agent of Nathaniel Noel (fl. 1681, d. c. 1753), bookseller, employed by Edward Harley for buying books and manuscripts chiefly on the Continent; acquired through him for the Harley Collection (for the details of the acquisition see 'Kirtisches Verzeichnis' 17 (1986), 21-56 and 10 (1973), 99).
- The Harley Collection, formed by Robert Harley (b. 1661, d. 1724), 1st earl of Oxford and Mortimer, politician, and Edward Harley (b. 1689, d. 1741), 2nd earl of Oxford and Mortimer, book collector and patron of the arts.
- Edward Harley bequeathed the library to his widow, Henrietta, née Cavendish Holles (b. 1694, d. 1755) during her lifetime and thereafter to their daughter, Margaret Cavendish Bentinck (b. 1715, d. 1785), duchess of Portland; the manuscripts were sold by the Countess and the Duchess in 1753 to the nation for £10,000 (a fraction of their contemporary value) under the Act of Parliament that also established the British Museum; the Harley manuscripts form one of the foundation collections of the British Library.