Ezra 6:15-19

Now this temple was completed on the third day of the month Adar; it was the sixth year of the reign of King Darius.

And the sons of Israel, the priests, the Levites, and the rest of the exiles, celebrated the dedication of this house of God with joy.

They offered for the dedication of this temple of God a hundred bulls, two hundred rams, four hundred lambs, and as a sin offering for all Israel twelve male goats, corresponding to the number of the tribes of Israel.

Then they appointed the priests to their divisions and the Levites in their sections for the service of God in Jerusalem, as it is written in the Book of Moses. The Passover Held

The exiles held the Passover on the fourteenth of the first month.