What is known clearly is that this Robert de Brus is first mentioned during the period 1094 and 1100, as a witness to a charter of Hugh, Earl of Chester, granting the church of Flamborough, Yorkshire, to Whitby Abbey. Possibly the Earl of Chester about 1100–1104 enfeoffed Robert of certain portions of his Cleveland fee in Lofthouse, Upleatham, Barwick, Ingleby, and other places. Between 1103–1106 Robert de Brus attested with Ralph de Paynel and 16 others a charter of William, Count of Mortain, to the abbey of Marmoutier. In 1109 at a Council of all England held at Nottingham, he attested the charter of King Henry I confirming to the church of Durham certain possessions which the men of Northumberland had claimed. During the period 1109–1114 he appears in early charters in possession of numerous other manors and lands in Yorkshire, and in the same period he attested a charter of Henry I issued at Woodstock, Oxfordshire. He appears in the Lindsey Survey made 1115–1118 in possession of even further lands. There is a strong presumption that the King had given Robert his Yorkshire fee soon after the battle of Tinchebrai (28 September 1106). Robert was present at the great gathering of northern magnates at Durham in 1121, and sometime during the period 1124–1130 he was with the King at Brampton. About 1131 he was in the retinue of Henry I at Lions, in Eure. At about the same time he attested with three of his personal knights a confirmation with Alan de Percy to the monks of Whitby. It is said that Robert had been given some 80 manors in Yorkshire by King Henry. It is evident that Robert kept up his connexions with other Normans too. A member of the Feugeres family, of Feugeres, Calvados, arr. Bayeux, canton of Isigny, witnessed charters of this Robert de Brus circa 1135 in Yorkshire.