ARTHUR, duke or count of Brittany (1187–1203), for whose death King John was responsible, was the son and heir of Geoffrey, third son of Henry II, who was killed in a tournament at Paris 19 Aug. 1186. His mother was Constance, daughter and heiress of Conan le Petit, count of Brittany. He was born after his father's death, on 29 March 1189. The Bretons hailed his birth with enthusiasm, and the bestowal upon him of the name of their national hero excited in them new hopes of independence, which was at the time seriously threatened by the ambitious designs of the kings of France and England.
The death of his grandfather, Henry II, in 1189 gave the infant Arthur a momentous political position. The principle of strictly hereditary succession made him the heir presumptive of his uncle, Richard I, to the exclusion of John, Henry II's fourth son. In order to repress John's dangerous ambition, Richard was anxious to assert Arthur's claim. In October 1190 he opened negotiations for the young prince's marriage with a daughter of Tancred of Sicily, and in a letter to Pope Clement III, dated 11 Nov. 1190, he distinctly declared his nephew his heir in case he should die childless. From that date John, who was plotting to supplant Richard I, viewed Arthur as his most dangerous enemy, and, according to one account, in 1191 entered into alliance with Philip II of France, who was willing to employ any means to injure English influence in France, to dispossess Arthur of all his rights (Annales Monastici, iii. 26). But this scheme proved for the present abortive; in March of the same year Philip agreed that Arthur should do homage to Richard as duke of Normandy, and, so as to gain a more effectual control over him later, for the five years following abstained from molesting him. In April 1196 the king of France had obtained sufficient influence with the prince and his mother to insure their open support in one of his constantly recurring quarrels with Richard, and the Breton nobles aided his policy by refusing to acknowledge the king of England as Arthur's guardian. But in August 1198 Richard contrived to reverse the position of affairs, and Arthur entered into an agreement with him to follow his guidance in his relations with France.
Eight months later Richard died, and Arthur was left face to face with John, who was resolved to succeed his brother in both France and England, and was crowned king of England 27 May 1199. The nobles of Anjou, Maine, and Touraine immediately declared for Arthur, as the son of Geoffrey, John's elder brother. Constance sent the boy to Philip II, who placed him at Paris under the care of his eldest son Lewis, a lad of exactly Arthur's age. At the same time Philip took possession of several castles, forming part of the dominions claimed by Arthur, on the plea of protecting them from John. He shortly afterwards knighted Arthur, and formally invested him with Brittany and with all Richard's French dominions—Anjou, Poitou, Maine, Touraine, and Normandy, John arrived in Normandy without delay, and with an army endeavoured to establish his power in France. A conference between Philip and himself took place on 16 and 17 Aug., but no terms were made, and in the hostilities that followed in October the French king's forces were driven from Maine. But Philip's high-handed treatment of those who acknowledged Arthur's sovereignty occasioned a breach between himself and the Bretons, and William des Roches, the leader of Arthur's forces, arranged a pacification between John and his nephew. This step was an unhappy one. John is said to have imprisoned Arthur, and to have so ill-used him and his mother that they fled from him with all haste to Angers, a town already in Arthur's possession. On 22 May 1200, while the dispute was still unsettled, Philip and John met at Vernon, and Arthur did homage to his uncle for Brittany and other lands, which do not appear to have been specified; but he remained in Philip's keeping, and took part in the tournament held at the time to celebrate the betrothal of Prince Lewis to Blanche of Castile. For the greater part of the year John was in England, and Arthur was at peace, but Philip was busy preparing an attack on Normandy. In 1201
