Eliashib was the high priest (3:1, 20; 13:28). He was evidently a close relative of Tobiah, the Jewish Ammonite leader who had opposed Nehemiah's efforts to rebuild the walls (2:19; 6:1, 17-18). Probably Eliashib cleaned out one of the temple storerooms and converted it into an apartment for Tobiah because he was an influential relative (v. 7). Nehemiah was very angry when he returned to Jerusalem and discovered this enemy of the faithful remnant living in the temple, so he threw him out.
"With this incident Nehemiah set the example of his new approach to an unnecessarily close relationship with foreigners. The purity of religion had to be maintained at any cost. This was absolutely necessary if the small community, beset as it was with all the temptations of paganism, was to be prevented from reverting to a compromise with the neighboring nations and bringing their ancestral religion into danger."87
Nehemiah could legitimately call Artaxerxes the king of Babylon in 539 B.C. Artaxerxes was, of course, a Persian king, not one of the kings of the Babylonian Empire. However in 539 B.C. Persia ruled Babylon.