Alger of Liège (1055-1131), known also as Alger of Cluny and Algerus Magister, a learned French priest who lived in the first half of the 12th century.

He was first a deacon of the church of St Bartholomew at Liège, his native town, and was then appointed (c. 1100) to the cathedral church of St Lambert. He declined many offers from German bishops and finally retired to the monastery of Cluny, where he died at great age and leaving a good reputation for piety and intelligence.

His History of the Church of Liège, and many of his other works, are lost. The most important of those still extant are: 1. De Misericordia et Justitia, a collection of biblical and patristic extracts with a commentary (an important work for the history of church law and discipline), which is to be found in the Anecdota of Martene, vol. v. 2. De Sacramentis Corporis et Sanguinis Domini; a treatise, in three books, against the Berengarian heresy, highly commended by Peter of Cluny and Erasmus. 3. De Gratia et Libero Arbitrio; given in B. Pez's Anecdota, vol. iv. 4. De Sacrificio Missae; given in the Collectio Scriptor. Vet. of Angelo Mai, vol. ix. p. 371.

See Migne, Patrol Ser. Lat. vol. clxxx. pp. 739-.972; Herzog-Hauck, Realencyk. für prot. Theol., art. by S. M. Deutsch.