Kuyaba (Arabic: كويابة Kūyāba[1]) was one of the three centers of the Rus[1][2] or Saqaliba (early East Slavs) described in a lost book by Abu Zayd al-Balkhi (dating from ca. 920) and mentioned in works by some of his followers (Ibn Hawqal, Al-Istakhri, Hudud ul-'alam). The two other centers were Slawiya (Arabic: صلاوية Ṣ(a)lāwiya)[1][2] (tentatively identified with the land of Ilmen Slavs, see Rus' Khaganate) and Arthaniya (Arabic: ارثانية ’Arṯāniya)(not properly explained).[1][2]
Soviet historians such as Boris Grekov and Boris Rybakov hypothesized that "Kuyaba" was a mispronunciation of "Kiev". They brought forth a theory that Kuyaba had been a union of Slavic tribes in the middle course of the Dnieper River centered on Kiev.[3] Kuyaba, Slaviya, and Artaniya later merged to form the state of Kievan Rus'. This explanation has been adopted by modern Ukrainian historiography.