The Annales Hanoniæ name "Raginerus" as son of "secundi Ragineri". The Gesta Episcorum Cameracensium records that "Rainerus atque Lantbertus, filii…Raineri", who had been banished by "archiepiscopus Bruno", returned to their father's lands after the death of Emperor Otto I and besieged "super Hagnam fluvium castrum Bussud", but that Emperor Otto II ordered their exile again. The Annales Leodienses, Floressienses et Marchianenses record that "Raginerus et Lantbertus" (sons of Reginar [III] Comte de Hainaut) returned from exile in 973 and killed "Guarnero et Rainaldo", who occupied their father's county, "apud Perronam" and besieged "super Hagnam fluvium castello Buxude". Thietmar records that "Lantbertus, Reinherii filius…cum fratre…Reingerio" killed "Wirinharium et eius germanum Reinzonem". Sigebert's Chronica records that in 977 "filii Ragineri" were "in terra partum suorum relocati", which presumably marked the beginning of their rehabilitation. Archbishop Egbert donated property "de beneficio Luthardi comitis…mortuo sine herede" to St Paul at Trier by charter dated 981, subscribed by "…Regeneri rerum S Marie advocatis…", although it is not known whether this is the same Reginar. A letter of Gerbert dated to  names "comes Reinharius". It is not clear from the context whether this refers to Reginar, son of Gozelon..., or Reginar [IV] Comte de Hainaut. However, a later letter names "Hainao Reniero" which suggests that the latter is correct. The Chronicle of Alberic de Trois-Fontaines records that "comes Raginerus" captured "Montem castri" from "comiti Godefrido" in 998, from which time REGINAR [IV] can properly be described as Comte de Hainaut, Comte de Mons. The Miracula S. Gisleni date one of the events recorded to "tempore Arnulfi et Raineri comitum…Hainacensium", which suggests that Arnoul continued to enjoy some jurisdictional rights in the county of Hainaut even after the restoration of Comte Reginar [IV].... "Raginero comite…et Hathuidis coniunx eius" donated property at Gion to Gembloux by charter dated to .
The Chronicle of Alberic de Trois-Fontaines records the death in 1013 of "in Haynico…comite Raginero Montense". 1