1 Chronicles 20:1-2

1And it came to pass, at the time of the return of the year, at the time when kings go outto battle, that Joab led forth the army, and wasted the country of the children of Ammon, and came and besieged Rabbah. But David tarried at Jerusalem. And Joab smote Rabbah, and overthrew it.

2And David took the crown of their king from off his head, and found it to weigh a talent of gold, and there were precious stones in it; and it was set upon David’s head: and he brought forth the spoil of the city, exceeding much.