In order to establish the list of Companions, we rely on the work of four prominent genealogists – Geoffrey H. White, Professor David Douglas, G. Andrew Moriarty and Anthony J. Camp.  Their work to establish the known Norman participants in the Battle of Hastings and their findings are summarized in the following publications:

  •         Complete Peerage, Vol. 12A, Appendix L by Geoffrey H. White
  •         Geoffrey H. White "Companions of the Conqueror" 10 May 1944, The Genealogists' Magazine, vol. 9, pp. 417-424 
  •         Professor David Douglas "Companions of the Conqueror" published in "History", the Journal of the Historical Association (Vol. XXVIII, pp. 129147) September 1943
  •         G. Andrews Moriarty "The Companions of the Conqueror" October 1944, The American Genealogist, Vol. 21 No.2, pp. 111-113
  •         Anthony J. Camp’s book My Ancestors Came with the Conqueror – summarizes and synthesizes the findings of his predecessors

But what sources did these prominent genealogists rely on?  They believe that there are three unimpeachable sources that unequivocally establish Companions who were at the Battle.  And those sources are:

  •         The Deeds of William II, Duke of the Normans and King of England by William of Poitiers. William of Poitiers was born about the year 1020 and belonged to an influential Norman family.  He wrote The Deeds of William II between 1071 and 1077.
  •          The Ecclesiastical History of Normandy and England by Orderic Vitalis.  Orderic Vitalis was born in England about 1075.  He began writing the Ecclesiastical History in about 1110 and continued until his death in 1142.  Although written almost 40 years later, it is considered to be a very reliable source.
  •         The Bayeux Tapestry, which was probably made in the late 11th century

And here is the list of Companions established by each of these sources (click on the links to connect to Wikipedia articles):

William of Poitiers
  1. Robert de Beaumont (+)
  2. Eustace of Boulogne (+)
  3. William of Evreux
  4. Geoffrey of Mortagne (+)
  5. William FitzOsbern (+)
  6. Aimery of Thouars (+)
  7. Hugh de Montfort (+)
  8. Walter Giffard (+)
  9. Ralph de Toeni (+)
  10. Hugh de Grandmesnil (+)
  11. William de Warenne (+)
  12. William Malet (+)
  13. Geoffrey de Mowbray

Bayeux Tapestry
    14.   Eudes (Odo) of Bayeux (+)
    15.   Robert of Mortain (+)
    16.   Wadard
    17.   Vital

Orderic Vitalis
    18.   Turstin FitzRou
    19.   Engenulf de l'Aigle (+)
    20.   Goubert d'Auffay (+)

However, of the 20 established Companions, only the 15 indicated by (+) have proven descendants.