Kilis has housed a long line of peoples — Babylonians, Hittites, Hurrians and Mitanni, Arameans, Assyrians, Persians, Macedonians, Romans, Byzantines, Seljuks, Mamluks and Ottomans — for the plain reason that the country here is good to settle in. The excavation at Oylum Höyük, about five kilometres south-east of the town centre, takes the district's history back to the Late Chalcolithic, between 3500 and 3000 BC.
The Hittite records place the district under the kingdom of Aleppo around 1460 BC. In later centuries it fell inside the territory of Alexander of Macedon as his eastward expansion took hold, and after his death in 323 BC it spent roughly 227 years under the Seleucids.
Rome annexed Kilis and its district in 64 BC, and under Roman rule the place was called Ciliza sive Urmagiganti. When the empire divided in 395 it stayed on the eastern side and was attached, together with Aleppo, to the Byzantine theme of Syria.
