On the top of Philadelphia’s late-19th-century city hall, which was intended to be the world’s tallest building, there rises a bronze statue, thirty-seven feet high, of William Penn (1644–1718), the English Quaker who founded Pennsylvania. His fame has derived not only from his colonial achievement but also from his ideal of religious liberty, which he eloquently and influentially advocated in England and established as a principle of his American territory. Yet the motives behind his colonial venture have been controversial. Admiring Quakers see it as a ‘holy experiment’, a term used about it by Penn himself in a stray remark of uncertain meaning. Sceptics view it as an exercise in real-estate investment. The province, granted to him by Charles II in a charter of 1681, was a hereditary property. Penn, who could never manage his money, looked to it to pay his debts and tried to extricate himself from the project when it deepened them.

After his death, Americans gave Penn bad marks as well as good. In the year of the Declaration of Independence, a Philadelphian pamphleteer thought it disgraceful enough that the ‘tyrant’ Charles had treated the inhabitants of the colony as disposable property, but remarked that Penn himself, ignoring ‘every sacred privilege of freedom’, had ‘carried the principle of tyranny higher than any of the Stuart family ever did’ by leaving Pennsylvania, in his will, to be sold back to the crown or any taker.

Penn’s life has always carried a mixed message in relation to liberal idealism. Even if he was the friend of religious freedom, what of its civil counterpart? Proponents of toleration in 17th-century England faced a recurrent dilemma, which was that parliamentary majorities, however friendly to political liberties, were routinely hostile