Mordecai, the eunuch Esther 2:7, Esther 2:11, has been conjectured to be the same as Matacas, who, according to Ctesias, was the most powerful of the eunuchs during the latter portion of the reign of Xerxes. Mordecai’s line of descent is traced from a certain Kish, carried off by Nebuchadnezzar in 598 B.C. - the year of Jeconiah’s captivity - who was his great-grandfather. The four generations, Kish, Shimei, Jair, Mordecai, correspond to the known generations in other cases, for example:
| High priests | kings of Persia | Royal stock of Judah |
| Seraiah | Cambyses | Jeconiah |
| Jozadak | Cyrus | Salathiel |
| Jeshua | Darius | Zerubbabel |
| Joiakim | Xerxes | Hananiah |
The age of Mordecai at the accession of Xerxes may probably have been about 30 or 40; that of Esther, his first cousin, about 20.