Reginald FitzUrse held the manors afterwards known as Barham Court in Barham and Barham Court in Teston, both in Kent , as well as estates in Northamptonshire and Leicestershire. It appears to have been the policy of the Normans Kings that their Barons and Knights should have their land widely scattered. Reginald was a Knight Attendant upon Henry II, the first of the Plantagenet Monarchs. His surname in Norman French signifies "Bear’s Son" and is doubtless derived from the "ourse:, or "urso" - "bear", of the age of the conquest. The representation of the murder of Becket, painted on the wood, which forms part of the tomb of Henry IV in Canterbury Cathedral, shows FitzUrse with the figures of bears on his surcoat. The original painting is much faded but a copy is displayed at the scene of the murder at the transept of martyrdom. In 1170, two years after he had inherited the manor of Willerton, FitzUrse took part in the assassination of the archbishop. Thomas Becket, formerly Chancellor, and a close friend of Henry II, who had made him Archbishop of Canterbury, was now involved in a violent quarrel with the King; over matters in which he believed that the rights of the Church, and in particular the See of Canterbury were in danger. Some hasty words with the King, then in his French dominions, indicated four knights of his household to under- take the removal of Becket. They were Reginald FitzUrse, Hugh de Moreville, William De Tracey, and Richard le Breton; FitzUrse being their leader. He by the way appears to have owed some allegiances to Thomas before the latter became Archbishop.
The conspirators crossed over to England , and gathered at Saltwood Castle , near Hythe. Saltwood was a possession of the Archbishop, but it had been usurped by Randolph de Brock, another of Beckets enemies. De Brock although privy to the plot did not take any part in the assassination. The visitor to the castle today is shown the ruins of the Hall in which it is believed the Knights met in the darkness and secrecy to make their plans. On the 29th of December, the Knights and their men rode forth from Saltwood to Canterbury , and sought out the Archbishop in his palace adjacent to the Cathedral. Bitter words and recriminations were exchanged in a fruitless interview. Later in the day the Knights again approached the palace with their weapons under their cloaks. The monks, anxious for their own safety as well as for their master, endeavoured to drag Becket through the cloisters into the sanctuary of the cathedral. He resisted, but they succeeded in getting him into the Northwest Transept, which is still known as the Martyrdom. They bolted the door behind them, but the Archbishop commanded it to be unbolted, lest the House of God be made a fortress. He began to make his way up the steps into the choir, where vespers were being sung, but as the knights burst in, he turned to meet them.
There was an altercation and a struggle in the gloom of the Transcept. FitzUrse called Becket "Traitor!", and Becket retorted with "Pander". The knights endeavoured in vain to drag the Archbishop out of the church. FitzUrse struck the first blow, a glancing one which injured the arm of an attendant monk. Tracey followed, and Le Breton smote the Archbishops skull with such violence that his sword was shattered on the stone of the pavement. Becket fell to the ground and was dispatched. The fourth knight, de Moreville, who had not struck a blow, was keeping back the townspeople who were pouring in from the knave. After the deed, the knights rushed out of the cathedral, waving their swords and shouting, "King's Men...King's Men". They pillaged the palace, and rode away to South Malling, near Lewes, where he had a manor. From thence they withdrew to Yorkshire , and took refuge in de Moreville's castle at Knaresborough.
At first, horror at the crime was mainly incited by the sacrilege committed in the Cathedral. The monks were not altogether sorry to be rid of the masterful Archbishop, of whose piety they might have had some doubt. When, however, the body of Becket was found to be clad with garments of haircloth beneath the archbishop's robes they were at length convinced by this evidence of his sanctity, that their Archbishop had indeed been one of themselves.
Soon the fame of the miracles wrought at the tomb of St. Thomas spread throughout England and Christendom, and brought thousands of pilgrims annually to pay their devotions and make their offerings at the shrine, which was first housed in the crypt, and then more splendidly in the Trinity Chapel behind the high altar.
The reputation of the Saint and Martyr lasted for over three centuries, until at length another Henry, Henry VIII, destroyed the shrine, and confiscated its accumulated riches and as far as lay in his power, blotted out the name and fame of the murdered archbishop. A lively account of these events can be read in Dean Stanley's "Historical Memorials of Canterbury Cathedral."
Henry II performed a public penance at the tomb of St. Thomas ; but what is the fate of the murderers themselves, and Reginald FitzUrse in particular? As the glory of the martyr grew with the years, the characters of punishment of the assassins were depicted in ever darker colours. It appears however, that their crime was regarded primarily as an offence against the Church, to be visited with spiritual rather than temporal penalties. The King himself could hardly avenge a murder which had been committed on his behalf, and at his instigation. The guilty knights were excommunicated by the Pope; in itself a heavy punishment in the 12th century. Later it is said they were sent to the Pope for judgement, and by him were ordered to go on a pilgrimage to the Holy Land . There, according to one story, they all died, and were buried at a place called the Black Mountain . Another more probable tradition asserts that FitzUrse either did not go to Palestine or that he returned thence alive, and passed over subsequently to Ireland . There he changed his name to Mayham which is said to signify Son of the Bear in the Erse language. It is a fact that many of the Anglo-Norman adventurers who fought to win from Henry the title of Lord of Ireland remained in that country to found families which in time merged into the native population. As the saying goes, "they became more Irish than the Irish". Religion was not then the dividing factor, which it became after the Reformation. Some corroboration of this tradition of the fate of FitzUrse is afforded by a statement of the Elizabethan poet Edmund Spenser, who filled an official post in Ireland . In his "View of the State of Ireland" he says, "The McMahons in the North were anciently English, to which descended of the FitzUrses, which was a noble family in England, and the same appeared by the significance of their Irish names. Likewise the McSweeneys, now in Ulster , were recently of the Veres in England , but they themselves had a hatred of the English, and so disguised their names".
The clan of the McMahons, whether or not descended from Reginald FitzUrse lived on for many centuries in Ireland . They remained faithful to the Roman Catholic faith, and the cause of the Stuarts. At the revolution of 1688 members of the clan followed James II into exile in France , and eventually became French citizens. Marshall McMahon (1808-1893), descendent of the exiles, and so perhaps of FitzUrse, was a great soldier who fought in the Franco-Prussian war of 1870, especially the communist insurrection that followed it. He served as President of the French republic from 1873-1879. It is said that the name and family of FitzUrse survived at Willerton in Somerset throughout the later Middle Ages until with the lapse of time, the Norman "FitzUrse" became in plain English Fisher.