Annes was the daughter of Robert ap Madog but her mother is unknown. The date and place of her birth have not been found.
Her husband was Gruffydd Voel ap Gruffydd. They were married, but the date and place have not been found. Their two known children were Ieuan ap Gruffydd Voel (?-?) and Dafydd ap Gruffydd Voel (?-?).