In the eighth month, in the second year of Darius, came the word of the LORD unto Zechariah, the son of Berechiah, the son of Iddo the prophet, saying, In the eighth month, in the second year of Darius - This was Darius Hystaspes; and from this date we find that Zechariah began to prophecy just two months after Haggai.
Son of Iddo - There are a number of various readings on this name, ידו Iddo, and עדוא Iddo, both in MSS. and in editions; but they are only different ways of writing the same name.