Thomas Grey, 15th Baron Grey de Wilton (died 1614) was an English aristocrat, soldier and conspirator. He was convicted of involvement in the Bye Plot against James I of England. Early life The son of Arthur Grey, 14th Baron Grey of Wilton, by his second wife Jane Sibella Morison, daughter of Sir Richard Morison, he served in the fleet against the Spanish Armada in 1588. He succeeded his father as Lord Grey of Wilton in 1593, and identified himself with the Puritans. Grey took part as a volunteer in the Islands Voyage of 1597. He was anxious to command a regiment; when Robert Devereux, 2nd Earl of Essex went to Ireland as Lord Deputy in March 1599, Grey was one of his followers, and received a commission as colonel of horse. Soon after his arrival in Ireland Essex asked him to declare himself his friend only, and to detach himself from Sir Robert Cecil but Grey declined on the ground that he was indebted to Cecil. Henceforth Essex and Essex's friend Southampton treated Grey as an enemy. In a small engagement with the Irish rebels fought in June he charged without directions from Southampton, who was general of horse and his superior officer. He was accordingly committed for one night to the charge of the marshal. The disgrace rankled in Grey's mind, and in May 1600 he abandoned Essex in Ireland, and with Sir Robert Drury (1575–1615) took a small troop of horse to serve the United Provinces in Flanders. Queen Elizabeth was incensed, but in July Cecil sent Henry Brooke, Lord Cobham and Sir Walter Raleigh to meet him at Ostend, and assure him of the queen's goodwill. This meeting at Ostend brought together for the first (and perhaps only) time Grey, Cobham, and Raleigh, who were afterwards charged with joint complicity in treason. Fighting under Maurice of Nassau, Grey took part in the battle of Nieuport, 2 July 1600, in which the Dutch gained a decisive victory over the Spanish forces under Albert VII, Archduke of Austria; Grey was wounded in the mouth. He sent home an account of the victory two days later. Grey was again in London early in 1601. In January, the queen warned Grey and Southampton to keep the peace, but Grey assaulted Southampton while on horseback in the street, and was committed to the Fleet Prison; Essex was deeply affronted. Grey was quickly