Albert Barnes Commentary Nehemiah 13:6

"But in all this [time] I was not at Jerusalem; for in the two and thirtieth year of Artaxerxes king of Babylon I went unto the king: and after certain days asked I leave of the king," — Nehemiah 13:6 (ASV)

Artaxerxes king of Babylon – See (Nehemiah 1:1). Compare (Ezra 6:22), where Darius Hystaspis is called “king of Assyria.”

After certain days – Or, “at the end of a year,” which is a meaning that the phrase often has (Exodus 13:10); (Leviticus 25:29–30); (Numbers 9:22). Nehemiah probably went to the court at Babylon in 433 B.C., and returned to Jerusalem in 432 B.C.