Baron Mowbray is a title in the Peerage of England. It was created by writ for Roger de Mowbray in 1283. It was held for a long time by the Mowbray and Howard Dukes of Norfolk. The title was united with the Barony of Segrave in 1368, when John Mowbray, 1st Earl of Nottingham and 5th Baron Mowbray succeeded to that title. Then, it became united with the Dukedom of Norfolk. The two titles were frequently separated due to the attainders of the Dukes of Norfolk, and were later reunited upon the Dukes' restorations. The final separation occurred with the death of the ninth Duke, when the barony of Mowbray fell into abeyance. Thereafter, it was united with the Barony of Stourton after it, and the barony of Segrave, were brought out of abeyance in the nineteenth century in favour of the twentieth Baron Stourton. The baronies of Mowbray and Segrave were shortly separated, as the barony of Segrave was called out of abeyance about two weeks after the barony of Mowbray. The Mowbray Barons become Premier Baron of England when the only older title, that of the Barony of de Ros (created by writ in 1264) is held by a woman.