FENWICK, SIR JOHN (c. 1645-1697), English conspira tor, son of Sir William Fenwick, was a strong partisan of King James II., and on the accession of William III. began at once to plot against the new king, for which he underwent a short im prisonment in 1689. He publicly insulted Queen Mary in 1691, and it is practically certain that he was implicated in the schemes for assassinating William which came to light in 1695 and 1696. After the seizure of his fellow-conspirators, Robert Charnock and others, he went into hiding, but was arrested in June, 1696. To save himself he offered to reveal all he knew about the Jacobite conspiracies; but his confession was a farce, being confined to charges against some of the leading Whig noblemen, which were damaging, but not conclusive. Sufficient evidence of treason was doubtful, but the Whigs secured the passage through parliament of a bill of attainder. Fenwick was beheaded in London on Jan. 28, 1697.