This saint was daughter of Pepin of Landen, eldest sister to Saint Gertrude of Nivelle, and married Ansegise, son to Saint Arnoul, who was some time mayor of the palace, and afterwards bishop of Metz. Her husband being killed in hunting, she dedicated herself to a penitential state of retirement, and, after performing a pilgrimage to Rome, built seven chapels at Anden on the Meuse, in imitation of the seven principal churches at Rome.
There she also founded a great nunnery in imitation of that which her sister governed at Nivelle, from which she was furnished with a little colony who laid the foundation of this monastery, and lived under her direction. Many holy virgins were trained up by them in the perfect practice of piety. The rich monastery of Anden was afterwards converted into a collegiate church of thirty-two canonesses of noble families, with ten canons to officiate at the altar. It is situate in the forest of Ardenne, in the diocess of Namur. Saint Begga departed to our Lord in the year 698, and is named in the Roman Martyrology.
Many ascribe to Saint Begga the institution of the Beguines, very numerous at Mechlin, Ghent, and other places in Brabant, the Flemish Flanders, and some neighbouring provinces of the Low Countries. They devote themselves to the divine service under simple vows of chastity, and certain pious rules, which only oblige so long as they remain in that state. But Ægidius Aureæ Vallis, and other historians inform us, that the Beguines were instituted by Lambert le Begue or Balbus, a pious priest of Liege, in 1170, and derived from him their name.