Heresy has been a concern in Christian communities at least since the writing of the Second Epistle of Peter: "even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them" (2 Peter 2:1). In the first two or three centuries of the early Church, heresy and schism were not clearly distinguished. A similar overlapping occurred in medieval scholasticism. Heresy is understood today to mean the denial of revealed truth as taught by the Church. Nineteenth-century theologian Friedrich Schleiermacher defined it as "that which preserved the appearance of Christianity, and yet contradicted its essence".