In his chronicle entry for 973,
Sigebert of Gembloux mentioned that Reginar and Lambert, sons of Reginar (III) Longneck, fought and killed
Count Werner and his brother
Rainold, who were occupying the county once held by Reginar III. They attacked at
Péronnes-lez-Binche and took a fort called "Buxude" above the
Haine, the river which Hainaut is named after. This was either
Boussu west of Mons, or
Boussoit to the east at
La Louvière. Among the sources which confirm this killing, the chronicle known as the deeds (
Gesta) of the bishops of Cambrai adds that the new young German emperor
Otto II, when he heard of this, gathered a force to besiege them, and then destroyed the castle, took them captive, and banished them from the country. The
Gesta claims that Werner and Rainold had been assigned by
Duke Bruno to govern Hainaut after the death of
Count Richar, who had died the year before. It also notes that after this defeat Lambert and his brother engaged in plundering and disturbances of the peace, and then withdrew to Carolingian-ruled northern France where they improved their military practices and gained the support of
Charles, Duke of Lower Lorraine, a rebellious younger brother of the French King
Lothair of France, who was one of the last ruling members of the
Carolingian dynasty, and Eudes, the son of his ally and kinsman
Adalbert I, Count of Vermandois. In his entry for 976 Sigebert mentioned that "the sons of Reginar Longneck" invaded Mons, this time with Charles. They fought against the counts
Godfrey "the captive" and
Arnulf of Valenciennes, who had been assigned the "county of Mons" after the deaths of Werner and Rainold. Godfrey and his family, which is today known as the
House of Ardenne, were Lotharingian adherents of the
Ottonian kings of Germany, and opponents of the Lotharingian claims of the French Carolingians. They held various bishoprics and counties throughout the 10th century. During the 10th and 11th century several of the dukes of upper and lower Lotharingia belonged to this family. In Sigebert's entry for the year 977, which mentions that Charles was made Duke of Lower Lorraine at this time, Lambert and his brother Reginar IV are also mentioned. The entry notes that Lambert married Gerberga, the daughter of Charles, and his brother Reginar IV married the daughter of another French king,
Hugh Capet, ancestor of the
Capetian dynasty. According to the historian
Ferdinand Lot, however, in 977 it was Charles who was married, and his daughter must have married later. Sigebert also mentioned that Lambert and his brother Reginar IV were relocated in the lands of their father (
in terra patrum suorum relocavit). It is believed that they did not yet have full control of the counties they would eventually hold, but for example historian Jean-Louis Kupper believes that they received part. In 978, the brothers fought on the side of France against
Otto II of Germany. Although they were described as counts, this was likely a reflection of personal status, and does not prove that they held specific territorial counties. In 985, several records indicate an alliance between the brothers and France. Duke Charles and Reginar IV attended an assembly with King Lothar in France, and after the capture of Godfrey I of Verdun (known as "the captive") one of the conditions for his freedom was the restitution of Mons to Reginar IV. This indicates that Reginar IV still did not have control of Mons. Before 995, Lambert was engaged in on-going conflict in or near the region of the
Pagus of Brabant (between the
Scheldt and
Dyle rivers), and one of his enemies was
Count Ansfried. This was reported in the early 11th century by
Alpertus of Metz, who described Count Lambert as having been a desperado, a leader of bandits (
praedones) who he preferred not to even name, and who profited from the blood and booty of the citizens, and then hid in forests and swamps. In contrast, Alpertus praised Count Ansfried, who became bishop of Utrecht in 995, saying he had often defeated the bandits in Brabant, but without disadvantaging the citizens in the way Lambert did. It was only in 998, at least according to
Alberic of Trois-Fontaines, that Reginar IV gained control of Mons. It is probable then, that Reginar IV did not receive Mons until after the death of his rival Godfrey "the captive", who is last recorded alive in 997. Lambert, on the other hand, was not described as a count of Leuven until 1003. In 1006, Lambert was an ally of the powerful
Counts of Flanders in their successful efforts to gain a foothold in the empire, east of the
Schelde. For this reason, the emperor Henry II held Lambert's son hostage. The entry of Flanders into Lotharingia was a major turning point, balancing the power of the House of Ardenne, and giving Lambert and his family a new long-run ally. Some time after 1010, Alpertus described Lambert as an ally (
cliens) of
Count Balderic, whose powerbase was around the area east of
Nijmegen near the modern border of Germany and the Netherlands. Lambert and
Count Gerhard of Metz, described as Balderic's closest friend, were called upon to besiege a new fortification made on the banks of the
Maas river, by his "Saxon" rival from north of the Rhine, . As the situation escalated Alpertus wrote that Gerhard and Lambert "said that they would endure travails and dangers" because "these two men were always prepared to stir up any kind of commotion or rebellion". Alpertus had more respect for other supporters of this clique during this dispute: the Bishop of Cologne;
Adalbold who had replaced Ansfried as bishop of Utrecht in 1010; and the emperor himself also gave them considerable grace. According to the chronicle of the deeds (
Gesta) of the bishops of Cambrai,
Balderic II, who became bishop of Liège in 1008, was a kinsman of Lambert, and thought it would be good to establish friendship with him. However, the bishop of Cambrai from 1012,
Gerard of Florennes, advised that he was unreliable, and was proven right by the subsequent battle of Hoegaarden. The text also claims that Gerard was influential in the appointment at this time of his own kinsman,
Godfrey II "the childless" son of Godfrey the captive and enemy of Lambert, as the new Duke of Lower Lotharingia, after the 1012 death of Duke Otto, the son of Lambert's old ally Duke Charles. In 1013 then, Lambert, with his nephew Reginar V, and
Robert II, Count of Namur, defeated Bishop Balderic at
Hoegaarden, after the bishop tried to fortify the town against the encroachments of Lambert into his territory. They captured the brother of Godfrey II,
Count Herman, the margrave of Ename, but he was given into the captivity of Count Robert, and soon released. Modern historians see this battle as one step in a long-term push by Lambert and his descendants to take control of the region to the east of Leuven, the county of
Brugeron, a part of the fertile
Hesbaye, which was in the possession of the prince-bishopric of Liège. ==Death==