On 11 July 1397, Richard II arrested his uncle Thomas of Woodstock, 1st Duke of Gloucester. Rutland was granted Gloucester's office of Constable of England on 12 July and was one of an eight-member commission that on 5 August determined to accuse Gloucester, the Earl of Warwick, and the Earl of Arundel of high treason. Rutland was later accused of having sent his servants to assist in Gloucester's subsequent murder at Calais, an allegation he denied. However, on 28 September 1397, he received a large grant of Gloucester, Warwick and Arundel's forfeited lands. On 29 September, he was created Duke of Aumale, a title that had earlier been granted to Gloucester on 3 September 1385.