Ezra left Babylon on the first day of the first month. In which month did he arrive in Jerusalem?

Answer: The fifth month

Ezra reached Jerusalem on the first day of the fifth month, in the seventh year of Artaxerxes, for the gracious hand of his God was on him.

“Ezra arrived in Jerusalem in the fifth month of the seventh year of the king. He had begun the journey from Babylon on the first day of the first month, and he arrived in Jerusalem on the first day of the fifth month, for the gracious hand of his God was upon him.”— Ezra 7:8-9 (BSB)