Margaret, Duchess of Norfolk

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.

Pope Clement VI granted papal dispensations for the marriages at the request of Henry of Grosmont, in order to prevent 'disputes between the parents'.

[12] She was most likely born at Framlingham Castle in Suffolk, England while her father Thomas de Brotherton was the 1st Earl of Norfolk.

She inherited the castle herself on her father's death Margaret married firstly, about 1335,[4] John Segrave, 4th Baron Segrave, by whom she had two sons and two daughters:[13] Shortly before 30 May 1354, Margaret married secondly, and without the King's license, Sir Walter de Manny, 1st Baron Manny,[14] by whom she had a son and two daughters:[9] As her brother had died without issue, she succeeded to the earldom of Norfolk and the office of Earl Marshal at her father's death in 1338.

Margaret is a character in Georgette Heyer's last novel My Lord John, where she is portrayed sympathetically as a kindly though outwardly formidable old lady.

In her last years, she is shown as being gravely concerned for the future of England, due to the misrule of her cousin King Richard II.