Gilbert was the Serjeant and Master Marshal of the royal household of king Henry I. His son John FitzGilbert succeeded his father as the Master Marshal, and supported the Empress Matilda during the civil war. Gilbert and Walter, his two sons from his first wife died childless. He divorced her and married Sibyl de Salisbury, by whom he had six children. His first son John, who was called John “the Marshal”, succeeded to part of his father’s lands in 1165, and to his half-brothers’ lands in 1166, as well as becoming Master Marshal.

The second son was William who, as a younger son, had no lands to inherit. Instead, he earned a good living by winning tournaments and becoming, according to Stephen Langton, “the greatest knight that ever lived”. He joined the royal household in 1170 to become mentor to Henry the Young King. His fortunes turned when in 1189 he married the 17-year-old Isabel de Clare, daughter of Richard “Strongbow” de Clare, the Earl of Pembroke and Striguil (Chepstow) in Wales and Leinster in Ireland, making him one of the richest men in the kingdom. Clementia de St. Clair, the widow of Hubert de St. Clair, was still living at the manor of Newberry, adjacent to the manor of Weston, where Eve MacMurchada, the daughter of the king of Leinster and Strongbow’s widow lived.

Like Hubert de Burgh, Justiciar of England, William became a staunch supporter of king John. Following the king’s death, William was appointed regent during the minority of John’s son, Henry III. However, his son William joined the barons and was excommunicated by the Pope. After his father, as regent, gained the approval of the barons for the coronation of Henry III, his son swore allegiance to the new king and profited handsomely.

William’s older brother John “the Marshal” married Joan de Port, but he only had one child, and that was by his mistress, Alice. John was killed defending Marlborough for king John in 1194, and his brother William succeeded him as Master Marshal. On 27 May 1199, William was invested as Earl of Pembroke by king John. On his deathbed in 1219, he joined the order of the Knights Templar and was buried in the Temple Church in London. William, his son, succeeded him as the 2nd Earl of Pembroke and became Justiciar for Ireland (1224-1226). Although the younger William married twice, he had no children, and his brothers Richard, Gilbert, Walter and Anselm each became earls of Pembroke and hereditary Marshals in succession. None, though, had any sons.

Meanwhile, John Marshall, the illegitimate son of John “the Marshal” married Aline [Aveline] de Rie about 1200, the daughter of Hubert de Rie of Hingham in Norfolk. Together with Roger de Cressy, John held 18 knights’ fees of the barony of Hubert de Rie in Norfolk and Suffolk, as well as fees in Cambridgeshire and Huntingdonshire. In a charter dated 11 November 1204, John gave land in Foulsham, Norfolk, to Walsingham priory for the souls of
himself and his wife Aline, for John and Alice, his father and mother, for William Marshall the Earl and Isabel his wife, and for Hubert and Margaret de Rye.
John and Aline had three children. The first was John, who held the office of Marshal of Ireland. King Henry III granted by a charter dated 28 November 1236, to “John son of John Marshall, that William Marshall, brother of the former, may supply his place in the office of the king’s Marshal of Ireland, granted to John Marshall senior by king John”. John died childless in October 1242.

His brother William married Elizabeth de Ferrers, and they had two children, another John and William. It was this William, born in 1277, who married Christian Fitzwalter, the daughter of Robert Fitzwalter and Devorguilla de Burgh. William was Lord Marshal in 1309 and in 1314 was killed at the battle of Bannockburn. Their son John succeeded as Lord Marshal, but died in 1317. Hawise, his sister became de jure Baroness Marshal on the death of her sister Denise. She married Robert de Morley, Lord Morley.