Five solae

The three solae or five solae (Latin: quinque solae from the Latin sola, lit. "alone"; occasionally Anglicized to five solas) of the Protestant Reformation are a foundational set of Christian theological principles theorized to be central to the doctrines of justification and salvation as taught by the Lutheranism, Reformed and Evangelical branches of Protestantism, as well as in some branches of Baptist and Pentecostalism.

Each sola represents a key belief in these Protestant traditions that is putatively distinct from the theological doctrine of the Catholic Church, although they were not assembled as a theological unit until the 20th century. The Reformers are known to have only stated two of the five solae clearly. Even today there are differences as to what constitutes the solae, how many there are, and how to interpret them to reflect the Reformers' beliefs.