Alger of Liège known also as Alger of Cluny and Algerus Magister, was a learned clergyman from Liège who lived in the first half of the 12th century.

He was first deacon

Deacon

Deacon is a ministry in the Christian Church that is generally associated with service of some kind, but which varies among theological and denominational traditions...

 of church of St Bartholomew

St Bartholomew's Church, Liège

Founded outside the city walls, the Roman Catholic Collegial Church of Saint Bartholemew in Liège, Belgium, was built in coal sandstone, from the late 11th century to the late 12th century , and underwent, like most religious buildings, modifications through the centuries...

 in his native Liège and was then appointed (c. 1100) to St. Lambert's Cathedral

St. Lambert's Cathedral, Liège

St. Lambert's Cathedral, Liège was the cathedral of Liège, Belgium, until 1794, when its destruction began...

. He declined offers from German bishops and finally retired to the monastery of Cluny

Cluny

Cluny or Clungy is a commune in the Saône-et-Loire department in the region of Bourgogne in eastern France. It is 20 km northwest of Mâcon.The town grew up around the Benedictine Cluny Abbey, founded by Duke William I of Aquitaine in 910...

, where he died at a high age, leaving behind a solid 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 (On Mercy and Justice), a collection of biblical extracts and sayings of Church Fathers with commentary (an important work for the history of church law and discipline), which is to be found in the Anecdota of Martène
   Edmond Martène
   Edmond Martène was a French Benedictine historian and liturgist....
   
   , vol. v.
2. De Sacramentis Corporis et Sanguinis Domini; a treatise, in three books, against the Berengar
   Berengar of Tours
   Berengar of Tours was a French 11th century Christian theologian and Archdeacon of Angers, a scholar whose leadership of the cathedral school at Chartres set an example of intellectual inquiry through the revived tools of dialectic that was soon followed at cathedral schools of Laon and Paris, ...
   
   ian heresy, highly commended by Peter of Cluny and Erasmus
   Desiderius Erasmus
   Desiderius Erasmus Roterodamus , known as Erasmus of Rotterdam, was a Dutch Renaissance humanist, Catholic priest, and a theologian....
   
   .
3. De Gratia et Libero Arbitrio; given in Bernard Pez's Anecdota, vol. iv.
4. De Sacrificio Missae; given in the Collectio Scriptor. Vet. of Angelo Mai
   Angelo Mai
   Angelo Mai was an Italian Cardinal and philologist. He won a European reputation for publishing for the first time a series of previously unknown ancient texts. These he was able to discover and publish, first while in charge of the Biblioteca Ambrosiana in Milan and then in the same role at the...
   
   , vol. ix. p. 371.

See Migne

Jacques Paul Migne

Jacques Paul Migne was a French priest who published inexpensive and widely-distributed editions of theological works, encyclopedias and the texts of the Church Fathers, with the goal of providing a universal library for the Catholic priesthood.He was born at Saint-Flour, Cantal and studied...

, Patrol Ser. Lat.

Patrologia Latina

The Patrologia Latina is an enormous collection of the writings of the Church Fathers and other ecclesiastical writers published by Jacques-Paul Migne between 1844 and 1855, with indices published between 1862 and 1865....

vol. clxxx. coll. 739-.972; Herzog-Hauck, Realencyk. für prot. Theol., art.

Schaff-Herzog Encyclopedia of Religious Knowledge

The Schaff–Herzog Encyclopedia of Religious Knowledge is a religious encyclopedia. It is based on an earlier German encyclopedia, the Realencyklopädie für protestantische Theologie und Kirche. Like the Realencyklopädie, it focuses on Christianity from a primarily Protestant point of...

by SM Deutsch.