In the year of the reign of Ahasuerus... they wrote an accusation, etc. Josephus (Antiquities XI, 2, 3) believes that this Artaxerxes, who received the letter of accusation from the Samaritans and forbade the construction of Jerusalem and the temple, was Cambyses, the son of Cyrus, who, after his father ruled for thirty years, reigned himself for eight years; and after him, the Magi ruled for one year, then Darius, the son of Hystaspes, succeeded to the throne. In his second year, the angel permitted the temple to be built, saying through Zechariah the prophet, interceding for the people: Lord of hosts, how long will you not have mercy on Jerusalem and the cities of Judah, against which you have been angry? This is the seventieth year (Zech. I). As for Ahasuerus, to whom it is said the letter of accusation was equally sent, it is perhaps silent on whether he replied or responded because either he died in the same year he began to reign, leaving the rule and these matters to Artaxerxes; or he was indeed contemporary with Artaxerxes but, being of lesser power, allowed him to handle and decide these things more.
Assuerus: Otherwise called Cambyses the son and successor of Cyrus. He is also in the following verse named Artaxerxes, a name common to almost all the kings of Persia.
[AD 735] Bede on Ezra 4:6