Roger Mortimer, 3rd Baron Mortimer of Wigmore, 1st Earl of March, was an English nobleman and powerful Marcher Lord who gained many estates in the Welsh Marches and Ireland following his advantageous marriage to the wealthy heiress Joan de Geneville, 2nd Baroness Geneville. Her mother was of the Royal House of Lusignan. In November 1316, he was appointed Lord Lieutenant of Ireland. He was imprisoned in the Tower of London in 1322 for having led the Marcher lords in a revolt against King Edward II in what became known as the Despenser War.

Joan de Geneville, 2nd Baroness Geneville, Countess of March, Baroness Mortimer, also known as Jeanne de Joinville, was the daughter of Sir Piers de Geneville and Joan of Lusignan. She inherited the estates of her grandparents, Geoffrey de Geneville, 1st Baron Geneville, and Maud de Lacy, Baroness Geneville. She was one of the wealthiest heiresses in the Welsh Marches and County Meath, Ireland. She was the wife of Roger Mortimer, 1st Earl of March, the de facto ruler of England from 1327 to 1330. She succeeded as suo jure 2nd Baroness Geneville on 21 October 1314 upon the death of her grandfather, Geoffrey de Geneville.