Sicilian historian Diodorus Siculus (ca. 100-30 BCE) is our only surviving source for a continuous narrative of Greek history from Xerxes' invasion to the Wars of the Successors following the death of Alexander the Great. Yet this important historian has been consistently denigrated as a mere copyist who slavishly reproduced the works of earlier historians without understanding what he was writing. By contrast, in this iconoclastic work Peter Green builds a convincing case for Diodorus' merits as a historian. Through a fresh English translation of a key portion of his multi-volume history (the so-called Bibliotheke, or 'Library') and a commentary and notes that refute earlier assessments of Diodorus, Green offers a fairer, better balanced estimate of this much-maligned historian.The portion of Diodorus' history translated here covers the period 480-431 BCE, from the Persian invasion of Greece to the outbreak of the Peloponnesian War. This half-century, known as the Pentekontaetia, was the Golden Age of Periclean Athens, a time of unprecedented achievement in drama, architecture, philosophy, historiography, and the visual arts. Green's accompanying notes and commentary revisit longstanding debates about historical inconsistencies in Diodorus' work and offer thought-provoking new interpretations and conclusions. In his masterful introductory essay, Green demolishes the traditional view of Diodorus and argues for a thorough critical reappraisal of this synthesizing historian, who attempted nothing less than a 'universal history' that begins with the gods of mythology and continues down to the eve of Julius Caesar's Gallic campaigns.