Edward Chamberlayne's State of England (1704) is by him. During 1699 and 1700, Wanley was engaged by George Hickes in searching through various parts of England for Anglo-Saxon manuscripts, and this led to his drawing up the catalogue of such manuscripts published in 1705 as the second volume of the Linguarum Veterum Septentrionalium Thesaurus of Hickes. The dedication (dated 28 August 1704) to Robert Harley, acknowledging the benefits received from him, was written in English and translated into Latin by Edward Thwaites. Wanley had been introduced by Hickes to Harley, on 23 April 1701, with the highest praise for "the best skill in ancient hands and manuscripts of any man, not only of this [...] but of any former age". This introduction and dedication later on procured Wanley's advancement. Wanley desired in December 1699 to be deputy-librarian to Bentley at the king's library, but this was denied him. The post of assistant to the secretary of the Society for Promoting Christian Knowledge, offered to him through the influence of Robert Nelson, on 16 December 1700, with a salary of £40 per year, was "thankfully accepted". He was promoted on 5 March 1701/2 to be secretary, with an annual salary of £70, and he retained the post until on or about 24 June 1708. Three letters from him relating to the society are printed in John Nichols's Illustrations of Literature, and to promote its objects he translated from the French J. F. Ostervald's Grounds and Principles of the Christian Religion (1704, 7th edit. 1765). The manuscript report of Wanley, John Anstis, and Matthew Hutton on the state of the Cottonian Library (dated 22 June 1703) is prefixed to a copy of Thomas Smith's Catalogue (1696) of the Cottonian manuscripts in the king's library at the British Museum. It also contains Wanley's manuscript catalogue of the charters in the collection. He communicated to Harley in 1703 the possibility of effecting the purchase of the Simonds d'Ewes collections, and they were bought through his agency in 1706. In 1708 he was employed by Harley to catalogue the Harleian manuscripts, and he then became "library-keeper" in turn to him and his son, the Edward Harley, 2nd Earl of Oxford and Earl Mortimer. By the time of his death he had finished the collation of No. 2407, and the catalogue remains as a monument of "his extensive learning and the solidity of his judgment". According