Human settlement at Erbil can be dated back to possibly 5000 BC, and it is one of the oldest continuously inhabited areas in the world. At the heart of the city is the ancient Citadel of Arbil. The earliest historical reference to the region dates to the Ur III dynasty of Sumer, when king Shulgi mentioned the city of Urbilum. The city was later settled by the Assyrians.
Erbil became an integral part of the kingdom of Assyria by at least the 21st century BC through to the end of the 7th century BC, after it was captured by the Gutians, and it was known in Assyrian annals variously as Urbilim, Arbela and Arba-ilu. After this it was part of the geopolitical province of Assyria under several empires in turn, including the Median Empire, the Achaemenid Empire (Achaemenid Assyria), Macedonian Empire, Seleucid Syria, Parthian Empire (Athura), Assyria (Roman province) and Sassanid Empire (Assuristan), as well as being the capital of the Neo-Assyrian state of Adiabene between the mid 2nd century BC and early 2nd century AD. Following the Arab conquest of Persia, Assyria as a geo-political entity (then known as Assuristan/Athura) slowly dissolved, and during medieval times the city came to be ruled by the Seljuk and Ottoman Turks.
Erbil's archaeological museum houses a large collection of pre-Islamic artefacts (particularly Sumerian and Assyrian) and is a centre for archaeological projects in the area. The city was designated as Arab Tourism Capital 2014 by the Arab Council of Tourism. In July 2014, Erbil Citadel was inscribed as a World Heritage Site by UNESCO.
The city has an ethnically diverse population of Kurds, Assyrians, Arabs, Armenians, Iraqi Turkmens, Yezidis, Shabakis and Mandeans. It is equally religiously diverse, with believers of Sunni Islam, Shia Islam, Christianity (mainly followed by Assyrians and Armenians), Yezidism, Yarsan, Shabakism and Mandeanism extant in and around Erbil.
The name Erbil was mentioned in Sumerian holy writings of third millennium BC as Urbilum, Urbelum or Urbillum, which appears to originate from Arbilum Later, the Akkadians and Assyrians by a folk etymology rendered the name as arba'ū ilū to mean (four gods). The city became a centre for the worship of the Assyro-Babylonian goddess Ishtar. In classical times the city became known as Arbela (Ἄρβηλα), from the Syriac language and Assyrian Neo-Aramaic form of the name. In Old Persian the city was called Arbairā.