A 14th century writer of the Gesta (chronicle) of the Abbey of St Truiden states that the parents of Giselbert and Balderic were Count Otto of Loon (otherwise unknown) and his wife Liutgarde, daughter of Countess Ermengarde of Namur, who was a daughter of Duke Otto of Lower Lotharingia.
Because of the very big gap in generations, two proposals have been made in which Otto, Count of Looz is accepted as father of Gilbert, but in a way which makes him Nevelong's grandson, adding a generation: In medieval records, Bishop Balderic II of Liège, about which more was written than his brothers, was said to be a kinsman of both Lambert I, Count of Louvain and Arnoul of Valenciennes.
[4] Balderic II, Giselbert's brother, donated his personal possessions at Pannerden in Batavia (Betuwe), near areas associated with the family of Nevelong, to the church in Liège.
Just before the Battle of Vlaardingen, where Balderic died of sickness on campaign, he was accused of wanting to spare a blood-relative, which implies a close relationship to Count Dirk III of Holland.
The third continuation of the medieval chronicle kept at the nearby abbey of St Truiden (Gestorum Abbatem Trudonensium Continuatio Tertia) states that Giselbert did not become count of Loon (Borgloon) until about 1021, after his brother Bishop Balderic II had already died in 1018, and it says there were some years between his father Otto's death and him taking up the position.
[9] But the Gesta of St Truiden appears to say that the same Lutgarde was the mother of Bishop Balderic II, the brother of Emmo's supposed father Gilbert.