For eighteen months the king reigned supreme. The barons could do nothing, and the Earl of Leicester, finding their cause hopeless, withdrew in August (1261) to France, and remained there until the spring of 1263, when he returned as the unquestioned head of the baronial party, to take up arms against the king. The citizens professed loyalty to Henry, who was residing in the Tower, and bound themselves by oath to acknowledge his son Edward as heir to the crown.(239) At Whitsuntide, the barons sent a letter to the king requiring him to observe the Provisions of Oxford, and shortly afterwards, addressed another letter to the citizens "desiring to be certified by them whether they would observe the said ordinances and statutes made to the honour of God in fealty to his lordship the king, and to his advantage of all the realm, or would, in preference, adhere to those who wished to infringe the same."(240) (M150) Before sending a reply, the citizens had an interview with the king in the Tower, to whom they showed the barons’ letter. The result was, that Henry availed himself of their services to mediate between him and the barons. A deputation of citizens accordingly travelled to Dover, where an understanding was arrived at between the hostile parties. The citizens were prepared to support the barons, subject to their fealty to the king and saving their own liberties; whilst the king promised to dismiss his foreign supporters—the real cause of all the mischief. Hugh le Despenser, whom Henry had deposed, was again installed justiciar of all England in the Tower; and the king and his family left the city for Westminster, the day after the barons entered it. "Thus was a league made between the barons and the citizens with this reservation—’saving fealty to his lordship the king.’"(241) (M151)