What is "nehardea"

Nehardea or Nehardeah ( "river of knowledge") was a city of Babylonia, situated at or near the junction of the Euphrates with the Nahr Malka (also known as Nâr Sharri, Ar-Malcha, Nahr el-Malik, and King's Canal), one of the earliest centers of Babylonian Judaism. As the seat of the exilarch it traced its origin back to King Jehoiachin. According to Sherira Gaon (Letter of Sherira Gaon, in Neubauer, M. J. C. i. 26), Jehoiachin and his coexilarchs built a synagogue at Nehardea, for the foundation of which they used earth and stones which they had brought, in accordance with the words of Psalms 102:15, from Jerusalem (comp. a similar statement in regard to the founding of the Jewish neighbourhood in the Persian city of Ispahan, in Monatsschrift, 1873, pp. 129, 181). For this reason it was called 'The Synagogue that Slid and Settled'. This was the synagogue called "Shaf we-Yatib," to which there are several references dating from the third and fourth centuries ( R. H. 24b; Avodah Zarah 43b; Niddah 13a), and which Abaye asserts ( Meg. 29a) was the seat of the Shekhinah in Babylonia. The Aaronic portion of the Jewish population of Nehardea was said to be descended from the slaves of Pashur ben Immer, the contemporary of King Jehoiachin ( Kiddushin 70b).