 Plutarch was writing over 400 years after Epaminondas's death and is therefore very much a secondary source, but he often explicitly names his sources, which allows some degree of verification of his statements.Some episodes of Epaminondas's life can be found in Plutarch's ""Lives"" of Pelopidas and Agesilaus II, who were contemporaries.There is also a surviving (and possibly abridged) biography of Epaminondas by the Roman author Cornelius Nepos from the first century BC which, in the absence of Plutarch's, becomes a major source for Epaminondas's life.