ADIAPHORISTS, the name of a party in the religious con troversies of the 16th century in Germany. The Adiaphorist controversy among Lutherans was an issue of the provisional scheme of compromise between religious parties, drawn up by Charles V., sanctioned at the Diet of Augsburg, May 1548, and known as the Augsburg Interim. It satisfied neither Catholics nor Protestants. As head of the Protestant party the young elector Maurice of Saxony negotiated with Melanchthon and others, and at Leipzig, Dec. 1548, secured their acceptance of the Interim as regards adiaphora (things indifferent), points neither enjoined nor forbidden in Scripture. This sanctioned jurisdiction of Roman Catholic bishops and observance of certain rites, while all were to accept justification by faith (relegating the words "by faith alone" to the adiaphora). Passionate opposition was led by Melanchthon's colleague, Matthias Flacius, on the grounds that the imperial power was not the judge of adiaphora, and that the measure was a trick to bring back popery. From Wittenberg he fled, April to Magdeburg, making it the headquarters of rigid Lutheranism. Practically, the controversy was concluded by the religious peace ratified at Augsburg (Sept. 1555), which left princes a free choice between the rival confessions with the right to impose either on their subjects; but much bitter internal strife was kept up by Protestants on the theoretical question of adia phora; to appease this was one object of the Formula Concordiae, 1577. Another Adiaphorist controversy between Pietists and their opponents, respecting the lawfulness of amusements, arose in 1681, when Anton Reiser (1628-86) denounced the opera as anti Christian.
See Herzog-Hauck, Realencykloplidie (3rd ed.) and Hastings, Encyclopaedia of Religion and Ethics, art. "Adiaphorism," where the connection of this historic question with the fundamental question of what is vital or essential is shown. For an earlier study, on rigorist lines, see E. Schmid, Adiaphora, wissenschaftlich u. historisch unter sucht (1809).