The church invisible, invisible church, mystical church or church mystical, is a Christian theological concept of an "invisible" Christian Church of the elect who are known only to God, in contrast to the "visible church"—that is, the institutional body on earth which preaches the gospel and administers the sacraments. Every member of the invisible church is "saved", while the visible church contains all individuals who are saved though also having some who are "unsaved". According to this view, Bible passages such as , , and speak about this distinction. The first person in church history to introduce a view of an invisible and a visible church is Clement of Alexandria. Some have also argued that Jovinian and Vigilantius held an invisible church view. The concept was advocated by St Augustine of Hippo as part of his refutation of the Donatist sect, though he, as other Church Fathers before him, saw the invisible Church and visible Church as one and the same thing, unlike the later Protestant reformers who did not identify the Catholic Church as the true church. He was strongly influenced by the Platonist belief that true reality is invisible and that, if the visible reflects the invisible, it does so only partially and imperfectly (see theory of forms). Others question whether Augustine really held to some form of an "invisible true Church" concept. The concept was insisted upon during the Protestant reformation as a way of distinguishing between the "visible" Roman Catholic Church, which according to the Reformers was corrupt, and those within it who truly believe, as well as true believers within their own denominations. John Calvin described the church invisible as "that which is actually in God's presence, into which no persons are received but those who are children of God by grace of adoption and true members of Christ by sanctification of the Holy Spirit... [The invisible church] includes not only the saints presently living on earth, but all the elect from the beginning of the world.