Ezra 8:17

And I sent them, undoubtedly by virtue of the authority vested in him, with commandment unto Iddo, the chief at the place Casiphia, this being either the name of a place between Ahava and Babylon or the designation of an office, that of treasurer to the king, and I told them what they should say unto Iddo, putting the very words of their commission into their mouths, and to his brethren, the Nethinim, at the place Casiphia, that they should bring unto us ministers for the house of our God. It seems evident from this statement that the Jews had kept their religious organization in Babylon at that time for more than a century, almost a hundred and fifty years, and had also enjoyed the privilege of free worship, even the Nethinim, who were beneath the Levites in the tasks of the Temple, having maintained their identity.