The Third Sacred War is a major event in Greek history of the fourth century. The problem of this conflict is fundamentally a problem of sources. Too often modern historians have been content to offer a linear reconstruction of the facts, modeled on the story of the book XVI of Diodorus Library, without the necessary work of criticism and deconstruction, which is the prerequisite for any true historical synthesis. This study will therefore seek to analyze all available sources (mainly epigraphic and literary) in a new light by applying rigorous historical criticism. The aim is to clarify the chronology of events and highlight the difficulties of the sources treatment.