The Middle Persian toponym Sūristān, used during the Sasanian period (224–651), had two meanings: Sūristān, another name for Asoristan,: "the Sāsānid province of Sūristān (Dil-i Ērāns̲h̲ahr)": "Locating the town [Wāsiṭ] on the mediaeval course of the Tigris in the ancient Sāsānid province of Sūristān, which was situated in the centre of Lower Mesopotamia or the Sawād, poses one of the most difficult problems of the historical geography of mediaeval Babylonia (M. Streck, EI 1 art. Wāsiṭ)." the Sasanian province also known as "Dil-i Ērānshahr" Sūristān, today's Kufa in Iraq, according to al-Baladhuri's account of the foundation of Kufa
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