This chapter deals with the Life of Plato which precedes the Alcibiades commentary. It focuses on the function of this biography, within the context of the isagogical questions, as a preparation to the commentaries on Plato which follow. The author analyses how Olympiodorus worked on older material, giving it philosophical consistency, and discusses possible didactic strategies, implications for Olympiodorus’ view on ethical development and intratextual links between the biography and the preserved commentaries. The hypothesis put forward is that Olympiodorus reveals how and why in Late Antiquity Plato's biography, influenced by Neoplatonist theories about the grades of excellence, served a protreptic function