The concept of ancient universal history — attempts to write the history of all known peoples from the beginning — is a Hellenistic innovation that reflects the cosmopolitan ambitions of the post-Alexander world. The pre-Alexandrian Greek historians (Herodotus and Thucydides) had focused on Greeks and their neighbors; the Hellenistic world demanded a broader canvas.

Diodorus Siculus, writing in the 1st century BC, produced a universal history in forty books covering from mythological origins to his own time. His history is of variable quality — it's largely compilation from earlier sources — but it preserves material from works now lost that would otherwise be completely unknown. Diodorus' account of the Sicilian Expedition, drawing on Timaeus' lost history, is the main alternative to Thucydides.

Poseidonius of Apamea (2nd-1st centuries BC) is the most important Hellenistic historian whose work is almost entirely lost. His history, continuing from Polybius, was drawn on by dozens of subsequent writers. Reconstructing Poseidonius from fragments is one of the more difficult exercises in ancient source criticism.

The universal history tradition combined with the Greek ethnographic tradition (Herodotus' descriptions of barbarian peoples) to produce a genre of comparative cultural description that influenced subsequent historical writing. The effort to understand all peoples in terms of a shared framework, however imperfect, represents a genuine intellectual achievement of the Hellenistic period.