The focus is on the meaning of ὑπόϑεσις in Irenaeus of Lyons’ Adversus haereses. Our case is to argue that two different elements converge in ὑπόϑεσις or its translations (especially argumentum) in the Latin version of AH. The first stems from the Greek literary field, in which ὑπόϑεσις means the “subject” or “plot” of a dramatic or poetic composition. The second is related to the philosophical meaning of ὑπόϑεσις as “that which is placed under” or “foundation”. On the one hand, Irenaeus uses ὑπόϑεσις theologically to express the plot of the historia salutis, so that the term can be understood as teaching or doctrine. On the other hand, this ὑπόϑεσις is at the same time a regula, the normative foundation of all the elements that take part in God’s economy of salvation.

At the beginning of Irenaeus of Lyons’ Adversus Haereses, the doctrine of the Valentinian Ptolemy is presented using terms from the semantic field of time and eternity, which were undergoing a semantic evolution in contemporary Middle Platonic philosophy. These allow us to identify three phases, from a chronological point of view, at the beginning of the Valentinian myth: strict, supra-durational, eternity – eternity of indefinite duration – moment ante tempus.