Q: WHAT YEAR DID DAVID BEGIN HIS 40-YEAR RULE OVER ISRAEL?
A: IT DEPENDS WHAT CALENDAR YOU ARE USING!
On the Gregorian calendar (the one you might have on your wall) the year was 999 BC.
On the Hebrew calendar, sometimes called the biblical calendar, the year was 3048 AM.
1 Kings 2:11 – The period that David reigned over Israel was forty years; seven years he reigned in Hebron, and in Jerusalem he reigned thirty-three years.
2 Samuel 5:4 - David was thirty years old when he began to reign, and he reigned forty years.