In the fourth year of Darius - Two years after the series of visions, shown to him, and two years before the completion of the temple. Chisleu being December, it was the end of 518 b.c.
Related Commentaries of Zechariah 7:1
Zechariah 7:1
1 And it came to pass in the fourth year of king Darius, that the word of the LORD came unto Zechariah in the fourth day of the ninth month, even in Chisleu;