Joshua 10:2
That they feared greatly, because Gibeon was a great city, as one of the royal cities, and because it was greater than Ai, and all the men thereof were mighty.
Nave's Topical Index—AKJV

1 Samuel 27:5
And David said to Achish, If I have now found grace in your eyes, let them give me a place in some town in the country, that I may dwell there: for why should your servant dwell in the royal city with you?
Nave's Topical Index—AKJV

2 Samuel 12:26
And Joab fought against Rabbah of the children of Ammon, and took the royal city.
Nave's Topical Index—AKJV

1 Chronicles 11:7
And David dwelled in the castle; therefore they called it the city of David.
Nave's Topical Index—AKJV