According to Winston Churchill, the Montgomeries (a very great house ofNorman England) sided with Robert, Duke of Normandy, against his brotherHenry I, in the war of succession after William Rufus, William TheConqueror's designated heir for England was killed in a huntingaccident. Henry I destroyed the power of the Montgomeries starting inSeptember, 1100. He captured Robert in Normandy in the battle atTinchebrai and combined England and Normandy again.
pg 113, "Ancestral Roots of Sixty Colonists, etc" by Frederick Lewis Weiss 6th edition