Irenism

Irenism (from Greek eirene - peace) was an ideology conceived by Dutch theologian Erasmus (1469-1538) after the consequences of the Reformation became apparent. It postulated removing conflicts between different Christian creeds by way of mediation and gradual amalgamation of theological differences. Irenical has become a commonly-used adjective to design an idealist and pacific conception, such as the democratic peace theory.

Although irenism did not play a major role in the theological climate of the 16th century, it is seen by some as forerunner to the more modern ecumenical movements.

An excellent description of an early irenic movemment can be found in Adam Nicolson's book God's Secretaries, which is about the making of the King James Bible. Nicolson believes that King James I wanted to avoid religious conflict between the Established English Church and the Puritan movements. James thought the Bible, whose creation was the job of several committees drawing on a variety of earlier translations, might effect some reconciliation between the not-quite-warring religious factions.

Unfortunately for everyone involved, that tension finally exploded in the English Civil War.

Philosopher Gottfried Leibniz was a supporter of irenism in the 18th century.

False irenism is an expression used by Pope Pius XII in the encyclical Humani Generis to criticize those who attempted ecumenism in a lousy way without realizing the consequences on related ecclesiology.