Charles Ellicott Commentary Ezra 4:6

"And in the reign of Ahasuerus, in the beginning of his reign, wrote they an accusation against the inhabitants of Judah and Jerusalem." — Ezra 4:6 (ASV)

In the beginning of his reign. —This Ahasuerus, another name for Cambyses, reigned seven years; and his accession to the throne was the time seized by the Samaritans for their “accusation,” of which we hear nothing more. It suffices that the building languished.