title: Merv
context: Under the Achaemenid Empire (c. 550–330 BC), the historical record mentions Merv as a place of some importance: under the name of Margu it occurs as part of one of the satrapies in the Behistun inscriptions (ca. 515 BC) of the Persian monarch Darius Hystaspis. The first city of Merv was founded in the 6th century BC as part of the Achaemenid expansion into the region[2] of Cyrus the Great (559–530 BC), but later strata deeply cover the Achaemenid levels at the site.
question: When was the city of Merv established?
answers: in the 6th century BC