There are indications that Robert may have been briefly betrothed to a daughter of King Cnut, but no marriage took place. It is unclear if William would have been supplanted in the ducal succession if Robert had had a legitimate son. Earlier dukes had been illegitimate, and William's association with his father on ducal charters appears to indicate that William was considered Robert's most likely heir. In 1034 the duke decided to go on pilgrimage to Jerusalem. Although some of his supporters tried to dissuade him from undertaking the journey, he convened a council in January 1035 and had the assembled Norman magnates swear fealty to William as his heir before leaving for Jerusalem. He died in early July at Nicea, on his way back to Normandy.