William Prynne (1600 – 24 October 1669) was an English lawyer, author, polemicist, and political figure. He was a prominent Puritan opponent of the church policy of the Archbishop of Canterbury, William Laud. Although his views on church polity were presbyterian, he became known in the 1640s as an Erastian, arguing for overall state control of religious matters. A prolific writer, he published over 200 books and pamphlets.
Born at Swainswick, near Bath, Somerset, he was educated at Bath Grammar School and Oriel College, Oxford. He graduated B.A. on 22 January 1621, was admitted a student of Lincoln's Inn in the same year, and was called to the bar in 1628. According to Anthony à Wood, he was confirmed in his militant puritanism by the influence of John Preston, who was then lecturer at Lincoln's Inn. In 1627 he published his first book, a theological treatise, followed in the next three years by three others attacking Arminianism and its teachers. In the preface to one of them he appealed to parliament to suppress anything written against Calvinist doctrine and to force the clergy to subscribe to the conclusion of the Synod of Dort. Prynne was ever the stark disciplinarian. After arguing that the custom of drinking healths was sinful, he asserted that for men to wear their hair long was 'unseemly and unlawful unto Christians,' while it was 'mannish, unnatural, impudent, and unchristian' for women to cut it short.