The likely ancestor of the Reginars,
Gilbert, Count of the Maasgau, a vassal of the
West Frankish king
Charles the Bald, married a daughter of the
Carolingian emperor
Lothair I in 846.
Reginar I "longneck", possibly his son, was the most powerful noble in the now kingless kingdom of
Lotharingia (Lorraine), in the period from 910 to 915. His son and successor
Gilbert swore fealty to the
East Frankish king
Henry the Fowler in 925 and three years later married his daughter
Gerberga of Saxony. His younger brother's son
Reginar III held lands in the region of
Mons. About 990,
Lambert the Bearded (d. 1015), son of Count Reginar III, married
Gerberga, daughter of the Carolingian duke
Charles of Lower Lorraine, and by 1003 he was being described as a Count of Louvain. His county, with its original capital of Louvain built upon the Dyle river, between the old
Pagus of Brabant and
Pagus of Hasbania, rapidly increased in size and power. In 1013, Lambert annexed part of the
county of Bruningrode, located between Louvain and
Tienen, and this became a source of long-running conflict with the prince-bishops of Liège. Lambert's family gained great influence in the
Holy Roman Empire, acquiring more comital titles over time. His son
Lambert II is also mentioned as a count of
Brussels, where he had the
St. Michael's Church erected to house the relics of
Saint Gudula. When he joined the rebellion of Count
Baldwin V of Flanders against
Emperor Henry III, he was killed in a 1054 battle at
Tournai. Lambert's grandson, Count
Henry III of Louvain was vested with the title of a
Landgrave of Brabant upon the death of the
Ezzonid count palatine
Hermann II of Lotharingia in 1085. In the early 12th century, Henry III was succeeded by his brother
Godfrey I, who was entrusted with the imperial Dukedom of Lower Lotharingia, and
Margraviate of Antwerp after
Henry of Limbourg fell out of favour. Although the title was later given back to the lords of
Limbourg-sur-Vesdre, Godefrey and his family refused to stop using the title, and kept possession of Antwerp. The ensuing conflict between the families led to the eventual abolishment of the Duchy, and the two families came to be known as the Dukes of Brabant and Limbourg respectively. ==Counts of Louvain and Brussels==