The Hellenica is Xenophon's account of Greek history modeled on Thucydides' History of the Peloponnesian War. It begins where Thucydides breaks off in 411 BC, during the final years of the war, and follows events down to the Battle of Mantinea in 362 BC. Although generally considered inferior to Thucydides, the Hellenica is an important source for the period it covers.
Free online and downloadable texts
Gutenberg: Hellenica, English translation by H.G. Dakyns. Multiple formats.
Loebulus. L088 - Xenophon -- Hellenica, Books 1-5. PDF of public domain Loeb edition in Greek and English.
Loebulus. L089 - Xenophon -- Hellenica, Books 6 and 7. Anabasis, Books 1-3. PDF of public domain Loeb edition in Greek and English.
Wikisource: Hellenica, English translation by H.G. Dakyns. Downloads via Book Creator.
BBC Radio 4 In Our Time: Xenophon. Melvyn Bragg with Paul Cartledge, Edith Hall and Simon Goldhill.
Internet Archive: A commentary with introduction and appendix on the Hellenica of Xenophon, by G.E. Underhill. (1900). Multiple formats.
The Great Conversation: Further reading at Tom's Learning Notes
Thucydides: History of the Peloponnesian War - Second major Greek historian.
Polybius: The Histories - another follower of the Thucydidean approach covering a somewhat later period.
Samuel Butler: Atlas of Ancient Geography (1841). Particularly: Asia Minor (3.9 MB) | Greece and Islands (3.6 MB) | Greece north of the Peloponnese (4.3 MB) | Greece and the Peloponnesus, South (3.8 MB) | Islands in the Aegean Sea (4.5 MB) |Macedonia, Moesia, Thracia, and Dacia (4.1 MB) | Oriens (Persia) (3.6 MB) Vindelicia, Rhaetia, Noricum, Pannonia, and Illyricum (3.0 MB)
Ancient Greek resources: Learn to read Greek classics in the original.