(Greek: satrapes, from Median khshathrapan, "protector of the realm")
Title of a provincial governor of the Achaemenid Empire. The satrapy system originated with the Medes, but was further refined by the Achaemenids. As ultimately defined by Darius I, the system was an expanded version of the gubernatorial office used in Assyria and Urartu.
The Old Testament makes frequent mention of the Persian satrapies (e.g. Ezra 8:36, Esther 9:3). Daniel 6:2 refers to 120 satrapies in the Persian Empire, whereas Herodotus mentions 20 satrapies.
When Alexander the Great conquered the Persian Empire, he retained the satrapy system, and it continued to function under his successors, the Parthians and Sassanids, albeit in modified form.