Hellenica (Ἑλληνικά) simply means writings on Greek (Hellenic) subjects. Several histories of fourth-century Greece, written in the mold of Thucydides or straying from it, have borne the conventional Latin title Hellenica. The surviving Hellenica is an important work of the Greek writer Xenophon and one of the principal sources for the final seven years of the Peloponnesian War not covered by Thucydides, and the war's aftermath.
Many consider this a very personal work, written by Xenophon in retirement on his Spartan estate, intended primarily for circulation among his friends, for people who knew the main protagonists and events, often because they had participated in them. Xenophon's account starts in 411 BCE, the year where Thucydides breaks off, and ends in 362 BCE, the year of the Battle of Mantineia. There is virtually no transition between the two works, to the extent that the opening words of Hellenica, μετὰ δὲ ταῦτα, are translated as After this, or sometimes Following these events.
Among competing works under this title, now lost, two stand out, that written by Ephorus of Cyme and that by Theopompus of Chios. Ephorus attempted a universal history, and though he attempted to set apart history from myth, he began his work with the legendary "Return of the sons of Heracles", which modern readers understand as wholly mythic aitia. As a pupil of the rhetorician Isocrates he was not above embroidering his narrative with believable circumstantial detail. Oswyn Murray remarked "His style and completeness unfortunately made him rather popular, but at least he stands out as one who had thought about the purposes that history should serve, and got them wrong." The Hellenica of Theopompus, another pupil of Isocrates, was a continuation of Thucydides.
Yet another, fragmentary Hellenica found in papyrus at Oxyrhynchus, is known as Hellenica Oxyrhynchia; it covered events from 411 to the year of the Battle of Cnidus, 395/4 BCE. It has been tentatively attributed to several historians.