Thomas Arnold (1795-1842) published Volume 2 of his edition of Thucydides' History of the Peloponnesian War in 1832. It contains Books 4-5, covering the war from the Spartan invasion of Attica in 425 B.C.E. to the defeat of the island of Melos by the Athenians in 415 B.C.E. The text and apparatus closely follow Bekker's 1821 critical edition. However, Arnold freshly collated a number of Greek manuscripts, including the important tenth-century Laurentian manuscript, which led to some revision of Bekker's text. Arnold's major contribution to Thucydidean scholarship lies in the detailed topographical and historical notes accompanying the text, which explain the geographical and political background to the History. For many generations Arnold's work has provided an indispensable guide through the complex geo-political context of the History, enabling students to appreciate its narrative, language and place in historiography.