Margaret of Norfolk or Margaret of Brotherton, in her own right Countess of Norfolk (sometimes surnamed as "Margaret Marshal"; –24 March 1399), was the daughter and eventual sole heir of Thomas of Brotherton, eldest son of King Edward I of England by his second marriage. In 1338, she succeeded to the earldom of Norfolk and the office of Earl Marshal. Family Margaret (b. about 1322), was the daughter of Thomas of Brotherton and Alice de Hales (d. in or before 1330). Her paternal grandparents were King Edward I and Margaret of France (1279?–1318), daughter of King Philippe III of France (d.1285). Her maternal grandparents were Sir Roger de Hales of Hales Hall in Loddon, Roughton, Norfolk by his wife Alice Skogan. She had a brother and sister: Edward of Norfolk, who married Beatrice Mortimer, daughter of Roger Mortimer, 1st Earl of March, but died without issue before 9 August 1334. Alice of Norfolk, who married Sir Edward Montagu. Life In 1335, Margaret was married to John Segrave, 4th Baron Segrave, and had four children - two sons and two daughters - by him. In 1350, she sought an annulment on the grounds that they had been contracted in marriage (in other words, betrothed) before she was of marriageable age, and that she had never consented to cohabit with him. She made known her intention of travelling to the continent in order to plead personally with the Pope for an annulment. King Edward III prohibited her from leaving England, but she set off incognito anyway, having taken care to obtain safe conduct from King Philip VI of France. Edward III's motivations were also to keep Margaret's children legitimate. If Margaret's marriage to her husband was annulled, then her children with John de Segrave, 4th Baron Segrave, would be considered illegitimate, damaging Edward III's plans for their marriages into the royal House of Plantagenet. John de Segrave, the son and heir of Margaret and the 4th Baron Segrave, was contracted to marry Blanche of Lancaster, the younger daughter and coheiress of Henry of Grosmont, 1st Duke of Lancaster, a second cousin of the King, and one of the King's most trusted captains. However, the marriage contract was later declared void, and Blanche instead married John of Gaunt, the third son of King Edward III; John of Gaunt received the title "Earl of Lancaster" by right of jure uxoris upon Henry of Grosmont's