The three princes, residing with their father in the castle of L’Aigle, in Normandy, were one day engaged in sport together, and after some mirth and jollity, the two younger took a fancy of throwing over some water on Robert as he passed through the court on leaving their apartment;[***] a frolic which he would naturally have regarded as innocent, had it not been for the suggestions of Alberic de Grentmesnil, son of that Hugh de Grentmesnil whom William had formerly deprived of his fortunes, when that baron deserted him during his greatest difficulties in England. The young man, mindful of the injury, persuaded the prince that this action was meant as a public affront, which it behoved him in honor to resent; and the choleric Robert, drawing his sword, ran up stairs, with an intention of taking revenge on his brothers.[****] [* Order. Vitalis, p. 545. Hoveden, p. 457. Flor. Wigorn. p. 639.] [** Chron. de Mailr. p. 160.] [*** Order. Vitalis, p 545] [**** Order. Vitalis, p 545] The whole castle was filled with tumult, which the king himself, who hastened from his apartment, found some difficulty to appease. But he could by no means appease the resentment of his eldest son who, complaining of his partiality, and fancying that no proper atonement had been made him for the insult, left the court that very evening, and hastened to Rouen, with an intention of seizing the citadel of that place.[*] But being disappointed in this view by the precaution and vigilance of Roger de Ivery, the governor, he fled to Hugh de Neufchatel, a powerful Norman baron, who gave him protection in his castles; and he openly levied war against his father.[**] The popular character of the prince, and a similarity of manners, engaged all the young nobility of Normandy and Maine, as well as of Anjou and Brittany, to take part with him: and it was suspected that Matilda, his mother, whose favorite he was, supported him in his rebellion by secret remittances of money; and by the encouragement which she gave his partisans. [* Order. Vitalis, p. 545.] [** Order. Vitalis, p. 545. Hoveden, 457, Sim. Dunelm. p. 210. Diceto, p. 487]