14th–15th centuries

"Tradition 1" and "Tradition 2" in the Late Middle Ages (after Oberman)

According to McGrath, for most medieval theologians Scripture was a materially sufficient source of doctrine. Heiko Oberman identified two concepts of Tradition. "Tradition 1" is the traditional way of interpreting Scripture within the community of believers, going back to patristic theologians such as Irenaeus – that is, a single-source theory. "Tradition 2," which took shape in the 14th–15th centuries, is an independent source of revelation, an oral Tradition from the apostles that supplements Scripture – that is, a two-source theory.