(Robert), a learned and pious English gentleman, was the son of Mr John Nelson a considerable Turkey merchant, and was born in June 1656. He had the first part of his education at St Paul's school, London; but the principal part was under a private tutor in his mother's house, after which he studied at Trinity College, Cambridge. In 1680 he was chosen a fellow of the Royal Society; being probably inclined to receive that honour out of respect to his friend and school-fellow Dr Edmund Halley, for whom he had a particular regard, and in whose company he set out on his travels abroad the December following. In the road to Paris, they saw the remarkable comet which gave rise to the comical astronomy by Sir Isaac Newton; and our author, apparently by the advantage of his fellow-traveller's instructions, sent a description of it to Dr, afterwards archbishop, Tillotson, by whom he was very much esteemed. From Paris he went with his fellow-traveller to Rome, where he fell into the acquaintance of Lady Theophila Lucy, widow of Sir Kingfisher Lucy of Broxburne in Hertfordshire, bart., and second daughter of George earl of Berkeley, who soon discovered a strong passion for him; this concluded in marriage, after his arrival in England in 1682. But it was sometime before she confessed to Mr Nelson the change of her religion; which was owing to her conversations at Rome with cardinal Philip Howard, who was grandson of the earl of Arundel, the collector of the Arundelian marbles, &c., and had been raised to the purple by pope Clement X. in May 1675. Nor was this important alteration of her religious sentiments confined to her own mind, but involved in it her daughter by her first husband, whom she drew over to her new religion; and her zeal for it prompted her even to engage in the public controversy then depending. She is supposed authoress of a piece written in 1686, 4to, under the title of, "A discourse concerning a judge of controversy in matters of religion, shewing the necessity of such a judge."

This misfortune touched her husband very nearly. He employed not only his own pen, but those of his friends Dr Tillotson and Dr Hickes, to recover her; but all proved ineffectual; and she continued in the communion of the church of Rome till her death. She was a person of fine sense and understanding. Dr Tillotson particularly laments her case on that account; and even seems not to be entirely free from all apprehensions of the influence she might have upon her husband in this important affair. But Mr Nelson's religion was too much the result of his learning and reason to be shaken by his love, which was equally steady and inviolable. Her change of religion made no change in his affections for her; and when she relapsed into such a bad state of health as obliged her to go and drink the waters at Aix, he attended her thither in 1688; and not liking the prospect of the public affairs at home, he proceeded to make a second trip to Italy, taking his lady, together with her son and daughter by her former husband, along with him. He returned through Germany to the Hague, where he laid some time with lord Dudley, who was married to his wife's sister.

From the Hague he arrived in England, in the latter end of 1691; where, being adverse to the Revolution, he declared himself a nonjuror, and left the communion of the church of England. In this last point he had consulted Dr Tillotson, and followed his opinion, who thought it no better than a trick, detestable in any thing, and especially in religion, to join in prayers where there was any petition which was held to be sinful. Thus, notwithstanding their difference of opinion in this case, the friendship between them remained the same; and the good archbishop expired in his friend's arms in 1694.

Our author's new character unavoidably threw him into some new connections. Among these we find mentioned particularly Mr Kettlewell, who had resigned his living at Coleshill in Warwickshire on account of the new oaths, and afterwards resided in London. This pious and learned divine also agreed with him in leaving the communion of the established church; yet at the same time persuaded him to engage in the general service of piety and devotion; observing to him, that he was very able to compose excellent books of that kind, which would be apt to do more good as coming from a layman. This address corresponded with the truly catholic spirit of our author; who accordingly published many works of piety, which are deservedly esteemed.

At the same time, he engaged zealously in every public public scheme for the honour and interest, as well as for propagating the faith, and promoting the practice of true Christianity, both at home and abroad; several proposals for building, repairing, and endowing churches, and charity-schools particularly.

Upon the death of Dr William Lloyd, the deprived bishop of Norwich, in the end of the year 1799, he returned to the communion of the church of England. Dr Lloyd was the last surviving of the deprived bishops by the Revolution, except Dr Kenn, by whose advice Mr Nelson was determined in this point. Mr Nelson's tutor, Dr George Bull, bishop of St David's, dying before the expiration of this year, he was easily prevailed upon by that prelate's son, to draw up an account of his father's life and writings, as he had maintained a long and intimate friendship with his Lordship, which gave him an opportunity of being acquainted with his solid and substantial worth. The life was published in 1733; and, as our author had long before laboured under a constitutional weakness, which had brought on an asthma and dropy in the breast, the distemper grew to such a height soon after the publication of that work, that, for the benefit of the air, he retired at length to Kensington, where he expired on the 16th of January 1714-15. He left his whole estate to pious and charitable uses; particularly to charity-schools.