Shirvan (from Persian: شروان, romanized: Shirvān; Azerbaijani: Şirvan; Tat: Şirvan), also spelled as Sharvān, Shirwan, Shervan, Sherwan and Šervān, is a historical Iranian region in the eastern Caucasus, known by this name in both pre-Islamic Sasanian and Islamic times. Today, the region is an industrially and agriculturally developed part of the Azerbaijan Republic that stretches between the western shores of the Caspian Sea and the Kura River, centered on the Shirvan Plain.