The cleric's support of Robert would have caused great trouble but Anselm returned before establishing any other terms than those offered by Henry. Once in England, Anselm was ordered by Henry to do homage for his Canterbury estates and to receive his investiture by ring and crozier anew. Despite having done so under William, the bishop now refused to violate canon law. Henry for his part refused to relinquish a right possessed by his predecessors and even sent an embassy to Pope Paschal II to present his case. Paschal reaffirmed Urban's bans to that mission and the one that followed it. Meanwhile, Anselm publicly supported Henry against the claims and threatened invasion of his brother Robert Curthose. Anselm wooed wavering barons to the king's cause, emphasizing the religious nature of their oaths and duty of loyalty; he supported the deposition of Ranulf Flambard, the disloyal new bishop of Durham; and he threatened Robert with excommunication. The lack of popular support greeting his invasion near Portsmouth compelled Robert to accept the Treaty of Alton instead, renouncing his claims for an annual payment of 3000 marks. Anselm held a council at Lambeth Palace which found that Henry's beloved Matilda had not technically become a nun and was thus eligible to wed and become queen. On Michaelmas in 1102, Anselm was finally able to convene a general church council at London, establishing the Gregorian Reform within England. The council prohibited marriage, concubinage, and drunkenness to all those in holy orders, condemned sodomy and simony, and regulated clerical dress. Anselm also obtained a resolution against the British slave trade. Henry supported Anselm's reforms and his authority over the English Church, but continued to assert his own authority over Anselm. Upon their return, the three bishops he had dispatched on his second delegation to the pope claimed—in defiance of Paschal's sealed letter to Anselm, his public acts, and the testimony of the two monks who had accompanied them—that the pontiff had been receptive to Henry's counsel and secretly approved of Anselm's submission to the crown. In 1103, then, Anselm consented to journey himself to Rome, along with the king's envoy William Warelwast. Anselm supposedly travelled in order to argue the king's case for a dispensation but, in response to this third mission, Paschal fully excommunicated the bishops who had accepted investment from Henry, though sparing the king himself. Second exile After this ruling, Anselm received