war is provided by the Sicilian historian Diodorus Siculus in books 12 and 13 of his Bibliotheca historica. Written in the first century BC, these books appear to be based heavily (possibly entirely) upon an earlier universal history by Ephorus, written in the century after the war, which is now lost. The Roman-Greek historian Plutarch wrote biographies of four of the major commanders in the war (Pericles, Nicias, Alcibiades and Lysander) in his Parallel Lives. Plutarch's focus was on the character and morality of these men, but he does provide some details on the progress of the war that are not recorded elsewhere. Written in the first century AD, Plutarch based his work on earlier accounts which are now lost. More limited information on the war is derived from epigraphy and archaeology, such as the walls of Amphipolis and grave of Brasidas, excavated in the 20th century. Some buildings and artworks produced during the war have survived, such as the Erechtheion temple and Grave Stele of Hegeso, both in Athens; these provide no information on military activity but do reflect civilian life during the war. Several plays by the Athenian Aristophanes were written and set during the war (particularly Peace and Lysistrata), but these are works of comedic fiction with little historical value. Prelude Thucydides summarised the situation before the war as: "The growth of the power of Athens, and the alarm which this inspired in Lacedaemon, made war inevitable." The nearly 50 years before the War had been marked by the development of Athens as a major power in the Mediterranean world. Its empire began as a small group of city-states, called the Delian League – from the island of Delos, on which they kept their treasury – that formed to ensure that the Greco-Persian Wars were over. After defeating the Second Persian invasion of Greece in the year 480 BC, Athens led the coalition of Greek city-states that continued the Greco-Persian Wars with attacks on Persian territories in the Aegean and Ionia. What ensued was a period which Thucydides called the Pentecontaetia, in which Athens increasingly became an empire, carrying out an aggressive war against Persia and increasingly dominating other city-states. Athens brought under its control all of Greece except for Sparta and its allies, ushering in a period now called the Athenian Empire. By mid-century, the Persians had been driven out of the Aegean and had ceded