This Roger was one of William the Conqueror's principal counsellors, playing a major role in the Council of Lillebonne by agreeing to contribute sixty ships for the invasion of England.

Also known as "Roger the Great", he would become the first Earl of Shrewsbury, Arundel and Sussex, and give the family name to the county of Montgomeryshire, in neighbouring Wales.

[4] After his death in 1094, the Welsh will organized an attack and conquer all their estates in Wales, leaving only Pembroke Castle standing to this day.

[5] At the beginning of the 12th century, the family will support Robert Curthose for the succession to the throne of England, following the death of William the Conqueror.

[6] Many members would be forced to exile, one of which would be Arnulf de Montgomery, who would make an alliance with the High King of Ireland, Muirchertach Ua Briain, by marrying his daughter.