Complex sentence: Eleanor was born in Brecknock, Breconshire, Wales in about 1228, the youngest daughter and co-heiress of the powerful Marcher lord William de Braose, 10th Lord Abergavenny, and Eva Marshal, both of whom owned considerable lordships and domains in the Welsh Marches and Ireland.
Split into simpler sentences: Eleanor was born in Brecknock, Breconshire, Wales in about 1228. She was the youngest daughter and co-heiress of the powerful Marcher lord William de Braose, 10th Lord Abergavenny, and Eva Marshal, both of whom held considerable lordships and domains in the Welsh Marches and Ireland.