The joyous dedication of the second Holy Temple (Beit HaMikdash) on the site of the 1st Temple in Jerusalem, was celebrated on the 3rd of Adar of the year 3412 from creation (349 BCE), after four years of work.
The First Temple, built by King Solomon in 833 BCE, was destroyed by the Babylonians in 423 BCE. At that time, the prophet Jeremiah prophesied: "Thus says the L-rd: After seventy years for Babylon will I visit you... and return you to this place." In 371 the Persian emperor Cyrus permitted the Jews to return to Judah and rebuild the Temple, but the construction was halted the next year when the Samarians persuaded Cyrus to withdraw permission. Achashverosh II (of Purim fame) upheld the moratorium. Only in 353 -- exactly 70 years after the destruction -- did the building of the Temple resume under Darius II.