פירוש על מלכים א 6:1

In the month of Ziv. This is Iyar because the trees have blossoms. And [Targum] Yonoson translated this similarly, “the bloom of the buds.”

Which is the second month. When numbering the months, because Nissan is the beginning of the year for [counting] months.

Of the reign of Shlomo. Referring to “the fourth year.”¹I.e., it does not mean “the second month of Shlomo’s reign,” rather it means the second month of the fourth year of Shlomo’s reign. It was the fourth year of Shlomo’s reign. And similarly it is stated in Divrei Hayomim, “And he began to build in the second month [on the second day] in the fourth year of his reign.”²II Divrei Hayomim 3:2.