Just before his death, he fulfilled a promise he said he made in his youth while on crusade by taking vows as a Knight Templar, and was buried in the Temple Church in London.

[6] William remained a crown hostage for many months, and was released following the peace resulting from the terms agreed at Winchester on 6 November 1153, by which the civil war was ended.

This would have included biblical stories, Latin prayers, and exposure to French romance literature to confer precepts of chivalry upon the future knight.

According to his thirteenth-century biography, L'Histoire de Guillaume le Marechal, Marshal had enemies at Tancarville's court who plotted against him—presumably men threatened by his close relationship with the magnate.

L'Histoire relates that the Earl of Essex, expecting the customary tribute from his valorous knight after the battle, jokingly remarked: "Oh?

Although Eleanor escaped unharmed, Patrick was killed; William was wounded in the thigh and was taken prisoner and conveyed to a Lusignan castle to be held for ransom.

Someone at the castle took pity on the young knight because it is told that he received a loaf of bread in which were concealed several lengths of clean linen bandages with which to dress his wounds.

He would remain a member of Eleanor's household for the next two years, taking part in tournaments and increasing his reputation as a chivalrous knight.

[13] Tournaments were dangerous, often deadly, staged battles in which money and valuable prizes were to be won by capturing and ransoming opponents, their horses and armour.

Historian Thomas Asbridge has stated that, while the affair very strongly appears to have been fabricated by William's political enemies within the Young King's service, it cannot be proven either way.

[18] Nothing is known of his activities during the two years he was gone, except that he fulfilled Young Henry's vow, and secretly committed to joining the Knights Templar on his deathbed.

The king gave William the large royal estate of Cartmel in Cumbria, and the keeping of Heloise, the heiress of the northern barony of Lancaster.

It may be that the king expected him to take the opportunity to marry her and become a northern baron, but William seems to have had grander ambitions for his marriage.

The letter by which he did this survives, and makes some sarcastic comments about William's complaints that he had not been properly rewarded to date for his service to the king.

In the resulting campaign, the king fell out with his heir Richard, count of Poitou, who consequently allied with Philip II against his father.

In 1189, while covering the flight of Henry II from Le Mans to Chinon, William unhorsed the undutiful Richard in a skirmish.

However, the marriage transformed the landless knight from a minor family into one of the richest men in the kingdom, a sign of his power and prestige at court.

[21] Even though the marriage was a reward for his political and military services, and despite a significant age difference, the couple appear to have developed a real love and affection for each other.

[25] When William paid homage to King Philip, John took offence and there was a major row at court which led to cool relations between the two men.

Though he left for Leinster in 1207 William was recalled and humiliated at court in the autumn of 1208, while John's justiciar in Ireland Meilyr fitz Henry invaded his lands, burning the town of New Ross.

Despite their differences, William remained loyal throughout the hostilities between John and his barons which culminated on 15 June 1215 at Runnymede with the sealing of Magna Carta.

He was preparing to besiege Louis in London when the war was terminated by the naval victory of Hubert de Burgh in the straits of Dover.

[2][23] William was criticised for the generosity of the terms he accorded to Louis and the rebels in September 1217, but his expedient settlement was dictated by sound statesmanship and a desire to remove the French from England as quickly as possible.

[28] By March, he realised that he was dying, so he summoned his eldest son, also William, and his household knights, and left the Tower of London for his estate at Caversham in Berkshire, near Reading, where he called a meeting of the barons, Henry III, the Papal legate Pandulf Verraccio, the royal justiciar (Hubert de Burgh), and Peter des Roches (Bishop of Winchester and the young King's guardian).

Through his granddaughter Maud de Braose, William is an ancestor to the last Plantagenet kings, Edward IV through to Richard III, and all English monarchs from Henry VIII and afterward.