Lady Margaret Courtenay was born on 13 April 1311, the first surviving daughter of Princess Elizabeth Plantagenet (daughter of King Edward I and Eleanor of Castile) and her second husband, Sir Humphrey de Bohun, Earl of Hereford and Essex.  Margaret had three older brothers, John and Humphrey (who each became Earl of Hereford and Essex in their turn) and William (who became Earl of Northampton).

On 11 August 1325, Margaret was married to Sir Hugh de Courtenay, who was born on 12 July 1303 and became 2nd Earl of Devon.  The Courtenays lived mainly at Tiverton Castle, with occasional visits to their castle at Okehampton.  They must have spent some time together and been on quite friendly terms as they had seventeen children (well, Margaret was a child bride after all)! 

Of these seventeen children, eight were sons and nine were daughters.  Their names were: Hugh, Edward (of Godlington), Thomas, Philip (of Powderham), Margaret, Elizabeth, Catherine, Joane, Matilda, Eleanor, Guinora, Isabell, Phillipa, William (who was Archbishop of Canterbury from 1381 to 1396), John, Peter and Humphrey.   

Sir Hugh, the 2nd Earl, died on 2 May 1377 and was succeeded as 3rd Earl by his grandson, Edward, son of Edward of Godlington.  Lady Margaret Courtenay lived for a further fourteen years, dying on 16 Dec 1391 at the age of eighty - a very long life in those times.  She was buried in Exeter Cathedral.