Isaac Newton was born on December 25, 1642, in a manor house in Woolthorpe, a village in the English county of Lincoln. He was a premature birth--so small, his mother Hannah Newton later remarked, that he might have been kept in a quart jug with room to spare--and surprised the midwives by surviving infancy. He survived fatherless--the elder Isaac Newton, a yeoman, or farmer of small means, had passed away three months before the birth of his son. Hannah, the wife he left behind, soon married again; when Isaac was only three, she wed an elderly, wealthy clergyman and moved away, leaving her firstborn son to be raised by his uncle. The clergyman, after fathering several step-siblings for young Isaac, died in 1653, and Hannah brought her new family home to the Woolthorpe manor. But from the age of three to the age of eleven, her fatherless eldest son had been bereft of a mother as well--a loss that Newton would continue to feel deeply for years, and that some biographers have seen as lying at the root of his later possessive qualities, and his fury when other scientists claimed authorship of theories and discoveries similar to his own.

Certainly, England in the 1640s was not a place to instill a sense of security and well-being in a young child. The decade was a turbulent time for the island nation: from 1642 to 1646, religious and political differences flared into a civil war between the forces of King Charles I and those backing the English Parliament. The Parliamentary forces won victory under the great general Oliver Cromwell, and they proceeded to execute Charles and do away with the monarchy (though only temporarily). In Newton's youth, England was governed by Cromwell, who took the title Lord Protector and ruled ruthlessly, if uneasily, over a nation riven by religious strife and brimming with political intrigue. These years saw the rise to power of the Puritans, the rigorous Protestants who had provided much of Parliament's muscle in the civil war, and who now dominated Cromwell's government. As their name suggested, the Puritans sought to "purify" Christianity: they saw vice and vanity everywhere, and they went about imposing their austere code on the entire country. Newton grew up in a nation whose government proscribed all non-Puritan forms of Christianity, closed theaters, frowned upon music (save for hymns), halted commerce on Sundays, and administered harsh, Old-Testament penalties for crimes like adultery. A grim, pessimistic form of religion thus pressed into every nook and cranny of English life.

Cromwell's Puritan dictatorship endured until 1660, although the Lord Protector himself died in 1658, leaving the nation in the hands of his genial son Richard, who proved incapable of holding on to what his father had won. After a brief period of disorder, Parliament invited Charles I's exiled son back to sit upon his father's throne, and on May 25, 1660, he returned to England to be crowned as Charles II. The new government disestablished Puritanism, and returned the Anglican Church to a more tolerant mode; the nation, released suddenly from a harsh theocracy, plunged into the fevered gaiety of the Restoration.

Newton was seventeen the year Charles returned. Lincolnshire, where he grew up, had generally backed Parliament during the civil war, but the Newtons were not religious extremists, and Newton himself would remain within the Church of England for his entire life, as a devout believer in the Christian God and the Bible's teachings (although as an Arian he doubted the absolute divinity of Christ). Meanwhile, his education proceeded throughout his youth: after attending two local schools near Woolthorpe, at age twelve he went to the larger Grantham Grammar School, located in nearby Grantham. The details of his childhood are dubious at best, since those who knew him did not write down their observations until years later, when he had already attained fame as Europe's greatest mind. Nevertheless, most accounts agree that he was a sober, quiet young man, ill at ease amid the rough-and-tumble of his schoolfellows. From a young age, he seems to have harbored a fascination for gadgets and odd contraptions, spending his free time tinkering with kites, water wheels, sundials, and clocks. But his inquisitive intelligence apparently failed to bring him success at school, where he was described as "idle" and "inattentive"--his mind was doubtless occupied with other--perhaps larger--matters.

His performance at Grantham was further disturbed by Newton's obligations in managing his mother's estate; and indeed, his family expected these duties to fill the rest of Isaac's life. Yet it appears that someone intervened--whether one of his schoolmasters, as some accounts suggest; or his maternal uncle, William Ayscough; or, as others claim, a mysterious stranger who supposedly came across the young Newton reading in a haystack--someone arranged for Newton in 1661 to leave Lincolnshire, and enroll as a subsizar (a kind of 17th-century "work-study" student) at Trinity College, Cambridge.