Patrocles the Historian (Πάτροκλος ὁ ἱστορικός) was a Greek historian and military commander who served under the Seleucid kings Seleucus I Nicator and Antiochus I Soter during the late 4th and early 3rd centuries BCE [1]. His career is known from later geographical works, which identify him as a trusted general and satrap of eastern regions, possibly including Media and areas near the Caspian Sea [1][2]. His floruit is generally placed circa 312–261 BCE [1].

His only known work, On the Caspian Sea (or a similar title), is lost but survives in fragments cited by later authors like Strabo and Pliny the Elder [1][2].

Patrocles is a significant, though fragmentary, source for the historical geography of the Hellenistic East. His influential, though later corrected, report described the Caspian Sea as a gulf of the Northern Ocean [1][2]. His accounts of Central Asian trade routes and peoples provided important data for later geographers like Eratosthenes and Strabo, linking the knowledge from Alexander's campaigns with Hellenistic scholarship [1].

Sources 1. Encyclopædia Britannica: https://www.britannica.com/biography/Patrocles 2. Perseus Digital Library, Strabo, Geography, Book 11, Chapter 7: http://www.perseus.tufts.edu/hopper/text?doc=Strab.+11.7&fromdoc=Perseus%3Atext%3A1999.01.0239