The teaching of philosophy was built around the study of authoritative texts and creative philosophical activity started to take the form of exegesis. This stance had important precedents in the Stoics' attitude towards Zeno, and especially in the way Epicureans treated Epicurus' writings, but from that time onwards it became ever more prominent among Aristotelians and Platonists. Apart from the doxographical sections, the principal stratum of Diogenes' work is constituted by the biographical tradition. Much of the later doxographical material ultimately goes back to Aristotle's surveys, and to the works composed by his disciples, some of which were specifically aimed at a methodical presentation of earlier views in various fields. In Damascius' interpretation, Eudemus' collection is evidence for the agreement of archaic sages and thus transmits elements of the same ancient wisdom that can be recovered by an inspired but also philologically attentive reading of Plato's authoritative text.