Mentioned in 1033[1]. Birth date (probably) estimated from this mention.
Gerard was a witness in 1042 as Gerarus Flamens[2] He was mentioned possibly again as a witness on March 23, 1053 as testerbant in comitatu Gerhardus comitis.[3] (Count of Wassenberg)
In 1064 he was listed as a witness as Gerard count of Gelre.[4]
Research notes
Ad Verschoor published a family tree[5] where Marguerite van Looz, daughter of Gislebert (Loon) van Loon (abt.0985-abt.1045) is mentioned as Gerard's wife.
In Charles Cawley, Medlands Project it appears that Gerard I and II are the same person, while other sources separate a Gerard I and II.
Abt 1013 - 1082 (69 years)