Anaximander was the first philosopher that used arche for that which writers from Aristotle onwards called "the substratum" (Simplicius Phys. 150, 22). He probably intended it to mean primarily "indefinite in kind" but assumed it also to be "of unlimited extent and duration". The notion of temporal infinity was familiar to the Greek mind from remote antiquity in the religious conception of immortality and Anaximander's description was in terms appropriate to this conception. This arche is called "eternal and ageless". (Hippolitus I,6, I;DK B2)