The Annales Hanoniæ name "Raginerus" as son of "Raginerus dictus Longi-colli". Flodoard names "Ragenarii, fratris ipsius Gisleberti". Charles III "le Simple" King of the West Franks restored Kloster Süsteren to the abbey of Prüm by charter dated 19 Jan 916 which names "fidelium nostrorum…Widricus comes palatii, Richuuinus comes, Gislebertus, Matfridus, Beringerius comites, Theodericus comes, Reinherus comes, Erleboldus". A document dated 7 Nov 921 recording a meeting between King Charles III "le Simple" and Heinrich I King of Germany names "Matfredus, Erkengerus, Hagano, Boso, Waltkerus, Isaac, Ragenberus, Theodricus, Adalardus, Adelelmus" as representatives of the former. It is not certain that "Ragenberus" refers to Reginar [II] Comte de Hainaut. Flodoard's Annals record that "Berengarius" captured "Giselbertum" and only freed him after receiving "filiis Ragenarii fratris ipsius Gisleberti" as hostages, after which Giselbert ravaged the lands of "Berengarii, Ragenariique fratris sui et Isaac comitis".
The primary source which confirms that Reginar [II] was Comte de Hainaut has not yet been identified. "Otto…imperator augustus" confirmed the donations to the convent of Nivelles by "Regenarius comes" of property "in pago Ardenna super fluvia Aisna in comitatu Waudricia in villa Villaro" and by "predicti Regenarii filius nomine Liechardus in pago Hasbanensi in villa Gingolonham", by "Rodolphus comes villa Lentlo", by "Hillinus…in villa…Gislebrertruoz…pro anima Gisloberti genitoris sui", and by "Robertus uxorque eius…Geua cum filio suo Regennario…in pago Hainau in villa…Hayna" by charter dated 24 Jan 966. This document presumably refers to Comte Reginar [II], as his son Reginar [III] was living in exile at the date of the charter. 1
Also referred to as Cte Régnier II DE HAINAUT.