Rādhān (or al-Rādhān, ) was a region in south central Mesopotamia (Iraq) in the early Middle Ages. It was an administrative district under the ʿAbbāsids and also a diocese of the Church of the East. It is also known to have had a Jewish population and was probably the country of origin of the Rādhānite merchants. The name, however, does not appear in any Hebrew texts. The exact location of Rādhān is not certain, but it was not far from Baghdad. It may have been roughly the same as the area known since the later Middle Ages as the Sawād, a fertile territory southeast of Baghdad on the eastern bank of the Tigris. Other authorities place it north of Baghdad, still east of the Tigris or further south of Baghdad and west of the Tigris in the region of Maishan. Cities that have been located in Rādhān include al-Madāʾin (ancient Seleucia-Ctesiphon), Dastagird, Baʿqūbā, Nahrwān, ʿUkbarā and Kilwādhā (now the eastern part of Baghdad). Terminology The spelling Rādhān reflects the Arabic. The Syriac form would be Radhan or Radhān. In one Arabic source it is Rāhdān. In Syriac and Christian Arabic sources, the term is usually singular. In early Islamic sources, however, the plural form Rādhānāt and the dual form Rādhānān are more common. They probably reflect the division of the territory into either a lower, middle and upper part or just a lower and upper part, respectively. Theodor Nöldeke argued that the name was of Assyrian origin and gave its hypothetical Assyrian form as ra-da-a-nu. In Syriac sources, Rādhān is identical to the region called Jūkhā in Arabic (Syriac Gōkhay or Gawkai). Rādhān-Gōkhay and Ṭīrhān are described as the two parts of the hyparchy (province) of Beth Aramaye in the Sasanian Empire. In Arabic usage, Jūkhā can refer to a land adjoining Rādhān or else a larger region of which Rādhān is a part. According to al-Ṭabarī, Upper Rādhān was in the arḍ (land) of Jūkhā. The term Rādhān had fallen out of use in favour of Sawād by later medieval times. Yāqūt al-Hamawī, writing around 1225, describes Lower Rādhān (Rādhān al-asfal) and Upper Rādhān (Rādhān al-aʿlā) as two districts in the Sawād of Baghdad. Two later Arabic writers, al-Bakrī and al-Suyūṭī, mistakenly describe it as a village, the former locating it in Baghdad and the latter (more correctly) in Sawād. History ʿAbbāsid district The Syriac Chronicle of Seert, records