Isaac Newton was born on January 4, 1643 (died March 31, 1727). While this astoundingly-talented English physicist, mathematician, astronomer, and natural philosopher is clearly one of the most influential scientists in human history, most of what’s generally known about him is more iconic/symbolic than real (think: countless Saturday morning cartoon depictions of apples falling on heads). In fact, Newton was an extraordinarily complex person with many interests beyond science and Enlightenment philosophy. As readers of Neal Stephenson’s Baroque Cycle are well aware, later in life, he became Master of the Royal Mint, and initiated a complete recoining of the nation’s currency.
As much as William Blake and others wanted to make him into a poster child for scientific reason and the death of the imagination/magic/spirit (what Blake dubbed “Newton’s sleep”), Newton was deeply religious (though, like Blake, unorthodoxly so) and actually wrote more about alchemy and religion than he did about the sciences. Ironically, upon his death, large amounts of mercury were found in his system, likely thanks to his years of alchemical practice. Many people use this fact as an explanation for some of his more eccentric views and behaviors later in life.
Here’s the Wikipedia entry on Newton.