Five solae

The five solae (from Latin, sola, lit. "alone"; occasionally Anglicized to five solas) of the Protestant Reformation are a foundational set of Biblical principles held by theologians and churchmen to be central to the doctrine of salvation as taught by Western Protestantism. Each sola represents a key belief in Protestant Christian faith in contradistinction to the teaching of the Roman Catholic Church. The Reformers claimed that the Catholic Church, especially its head, the Pope, had usurped divine attributes or qualities for the Church and its hierarchy.

The solas were not systematically articulated together until the 20th century. But sola gratia and sola fide were used in conjunction by the Reformers themselves. For example, in 1554 Melanchthon wrote, "sola gratia justificamus et sola fide justificamur" ("only by grace do we justify and only by faith are we justified"). All of the solas show up in various writings by the Protestant Reformers, but they are not catalogued together by any.

In 1916, Lutheran scholar Theodore Engelder published an article titled "The Three Principles of the Reformation: Sola Scriptura, Sola Gratia, Sola Fides" ("only scripture, only grace, only faith"). In 1934, theologian Emil Brunner substituted Soli Deo gloriam for Sola Scriptura. In 1958, historian Geoffrey Elton, summarizing the work of John Calvin, wrote that Calvin had "joined together" the "great watchwords". Elton listed sola fide with sola gratia as one term, followed by sola scriptura and soli Deo gloria. Later, in commenting on Karl Barth's theological system, Brunner added Christus solus to the litany of solas while leaving out sola scriptura. The first time the additional two solas are mentioned is in Johann Baptiste Metz's 1965, The Church and the World.

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