ADALBOLD: Bishop of Utrecht; d. Nov.27, 1026. He was born probably in the Low Countries, and received his education partly from Notker of Liege. He became a canon of Laubach, and apparently was a teacher there. The emperor Henry II., who had a great regard for him, invited him to the court, and nominated him as Bishop of Utrecht (1010), and he must be regarded as the principal founder of the territorial possessions of the diocese, especially by the acquisition in 1024 and 1026 of the counties of Thrente and Teisterbant. He was obliged to defend his bishopric not only against frequent inroads by the Normans, but also against the aggressions of neigh-boring nobles. He was unsuccessful in the attempt to vindicate the possession of the district of Merwede (Mirevidu), between the mouths of the Maas and the Waal, against Dietrich III. of Holland. The imperial award required the restitution of this territory to the bishop and the destruction of a castle which Dietrich had built to control the navigation of the Maas; but the expedition under Godfrey of Brabant which undertook to enforce this decision was defeated; and in the subsequent agreement the disputed land remained in Dietrich's possession. Adalbold was active in promoting the building of churches and monasteries in his diocese. His principal achievement of this kind was the completion within a few years of the great cathedral of St. Martin at Utrecht. He restored the monastery of Thiel, and completed that of Hohorst, begun by his predecessor Ansfried. To the charge of the latter he appointed Poppo of Stablo, and thus introduced the Cluniac reform into the diocese.

Adalbold is also to be mentioned as an author. A life of Henry II., carried down to 1012, has been ascribed to him; but the evidence in favor of attributing to him the extant fragment of such a life (MGH, Script., iv., 1841, 679-695; MPL, cxl. 87-108) is not decisive. He wrote a mathematical treatise upon squaring the circle (MPL, cxl. 1103-08), and dedicated it to Pope Sylvester II., who was himself a noted mathematician. There is also extant a philosophical exposition of a passage of Boethius (ed. W. Moll in Kerkhistorisch Archief, iii., Amsterdam, 1862, pp. 198-213). The discussion Quemadmodum indubitanter musicae consonantiae judicari possint (ed. M. Gerbert, in Scriptores ecclesiastici de musica sacra, i., St. Blasien, 1784, pp. 303-312; MPL, cxl. 1109) seems to have been ascribed to him on insufficient grounds. (A. HAUCK)

BIBLIOGRAPHY: Van der Aa, Adelbold, bisschop van Utrecht, Utrecht. 1862; Hauck. KD, iii.