Thomas Maude's ‘Wensleydale,’ 1771, and in Turnor's ‘Collections for the History of Grantham,’ 1806, p. 157. He was baptised at Colsterworth 1 Jan. 1642–3. His father, Isaac Newton of Woolsthorpe, had married in April 1642 Hannah, daughter of James Ayscough of Market Overton, Rutland, but died at the age of thirty-six, in October 1642, before the birth of his son. The small estate of Woolsthorpe had been purchased by the philosopher's grandfather, Robert Newton (d 1641), in 1623. Some three years after her first husband's death, 27 Jan. 1645–6, Newton's mother married Barnabas Smith, rector of North Witham, Lincolnshire, who died in 1656, leaving by him one son, Benjamin, and two daughters, Marie (wife of Thomas Pilkington of Belton, Rutland) and Hannah (second wife of Thomas Barton of Brigstock, Northamptonshire).

On his mother's second marriage Newton was left at Woolsthorpe in charge of his grandmother, Mrs. Ayscough. He was sent in 1654 to the grammar school at Grantham, then kept by a Mr. Stokes. For some time he made little advance with his books, but a successful fight with a boy older than himself awakened a spirit of emulation, and Newton soon rose to be head of the school. At the age of fourteen he was removed from school by his mother, who had returned to Woolsthorpe on the death of her second husband, in order to take part in the management of her farm. This proved distasteful to Isaac—there are various stories of the way in which he occupied himself with mathematics and other studies when he ought to have been attending to his farm duties—and by the advice of his uncle, William Ayscough, rector of Burton Coggles, Lincolnshire, he was sent back to school in 1660 with a view to preparing him for college. Ayscough was himself a Trinity man, and on 5 June 1661 Isaac Newton was matriculated as a subsizar at Trinity College, Cambridge, under Mr. Pulleyne. Few details of his undergraduate life remain. In 1664 he made some observations on halos, afterwards described in his ‘Optics’ (bk. ii. pt. iv. obs. 13), and on 28 April of the same year he was elected a scholar. He graduated B.A. in January 1665, but unfortunately the ‘ordo senioritatis’ for that year has not been preserved.

Newton's unrivalled genius for mathematical speculation declared itself almost in his boyhood. Before coming to Cambridge he had read Sanderson's ‘Logic’ and Kepler's ‘Optics.’ As an undergraduate he applied himself to Descartes's ‘Geometry’ and Wallis's ‘Arithmetica Infinitorum,’ and he attended Barrow's lectures. His mental activity immediately after taking his degree, during 1665 and 1666, was extraordinary. In a manuscript quoted in the preface to ‘A Catalogue of the Newton MSS., Portsmouth Collection,’ Cambridge, 1888, written probably about 1716, he writes: ‘In the beginning of the year 1665 I found the method for approximating series and the rule for reducing any dignity [power] of any binomial to such a series [i.e. the binomial theorem]. The same year in May I found the method of tangents of Gregory and Slusius, and in November had the direct method of Fluxions [i.e. the elements of the differential calculus], and the next year in January had the Theory of Colours, and in May following I had entrance into the inverse method of Fluxions [i.e. integral calculus], and in the same year I began to think of gravity extending to the orb of the Moon … and having thereby compared the force requisite to keep the Moon in her orb with the force of gravity at the surface of the earth, and found them to answer pretty nearly. All this was in the two years of 1665 and 1666, for in those years I was in the prime of my age for invention, and minded Mathematics and Philosophy more than at any time since’ (see also Appendix to Rigaud's *Essay on the Principia*, pp. 20, 23; ‘Letter to Leibnitz,’ 24 Oct. 1676, No. lv. in the *Commercium Epistolicum*; Pemberton, Preface to *A View of Sir Isaac Newton's Philosophy*, 1728). Another statement referring to these early years, quoted by Brewster in his ‘Life of Newton,’ from a notebook among the Conduitt papers in the possession of Lord Portsmouth, under date 4 July 1699, runs as follows: ‘By consulting an account of my expenses at Cambridge in the years 1663 and 1664, I find that in the year 1664, a little before Christmas, I being then Senior Sophister, bought Schooten's “Miscellanies” and Carte's “Geometry” (having read his “Geometry” and Oughtred's “Clavis” clean over half a year before), and borrowed Wallis's works, and by consequence made these annotations out of Schooten and Wallis in winter between the years 1664 and 1665. At such time I found the method of infinite series; and in summer 1665, being forced from Cambridge by the plague, I computed the area of the hyperbola at Boothby in Lincolnshire to two-and-fifty figures by the same method.’

Newton states here that he was driven from Cambridge in 1665 by the plague, while he wrote in the ‘Philosophical Transactions’ (vi. 3075): ‘In the beginning of the year 1666 … I procured me a triangular glass prism to try therewith the celebrated phenomena of colours,’ and continues (p. 3080): ‘Amidst