William, an eminent divine of the church of England, was born at Oxford in 1602, and educated at Trinity College, of which he was elected a fellow in 1628. He early made great proficiency in his studies, and distinguished himself especially in divinity, mathematics, and versification. During his residence at the university the controversy between the church of England and that of Rome formed the principal subjects of study and conversation, especially in relation to the king's marriage with Henriette, daughter of Henri IV. king of France: and Chillingworth, chiefly at the instigation of the Jesuit Fisher, was induced to abandon the communion of the Church of England and embrace the Roman Catholic faith. Laud, then bishop of London, hearing of this decisive step, and of his retreat to Douay, corresponded with him on the subject and induced him to return to Oxford and re-examine the whole question. This new inquiry resulted in his return to his former faith. In 1634 he wrote a confutation of the arguments which had induced him to join the communion of the Church of Rome; but, at the same time, the freedom with which he spoke of his difficulties gave rise to a groundless report that he had turned Catholic a second time, and then Protestant again. His return to the communion of the Church of England attracted a large share of public attention, and engaged him in controversy with several distinguished Jesuits. In 1635 he engaged in a work designed as an answer to a book entitled Charity Mistaken, by a Jesuit of the name of Mathias Wilson, which furnished him with a better opportunity of confuting the principles of the Church. of Rome, and of vindicating the Protestant religion. It was published under the title *The Religion of Protestants a safe Way to Salvation*. About the same time Sir Thomas Coventry, lord keeper of the great seal, offered him preferment; but Chillingworth declined to accept it, on the ground of his scruples with regard to the subscription of the thirty-nine articles. These, however, he ultimately surmounted; and being promoted to the chancellorship of the church of Sarum, with the prebend of Brixworth in Northamptonshire annexed to it, he complied with the usual subscription. Chillingworth was zealously attached to the royal party; and, in August 1643, was present in Charles's army at the siege of Gloucester, where he suggested and directed the construction of certain engines for assaulting the town. Soon afterwards, having accompanied Lord Hopton, general of the king's forces in the west, to Arundel Castle in Sussex, he was taken prisoner by the parliamentary forces under the command of Sir William Waller, who compelled the garrison to surrender. A sudden illness necessitated his separation from the troops who were returning to London, and he was removed to Chichester, where he died in 1644. His character has been delineated by Anthony Wood, by Archbishop Tillotson, and by Lord Clarendon. His theological and controversial pieces have been often reprinted, and form standard works on the subjects of which they treat.