 Her father Fergus, Earl of Buchan, had no male heirs and so in marrying his daughter to William he ensured a suitable line for his titles before his death.Dying sometime around 1214 (perhaps earlier) William took over the management of the mormaerdom (earldom) of Bucham, by right of his wife.William (is believed to have) had six children through his first wife Sarah Fitzhugh and eight through Marjory, Countess of Buchan.