What's the Kennection? #84

Our English word for a royal dwelling comes from what centermost of the Seven Hills of Rome, where the Flavian emperors lived?

What was the Latin name for the city of Troy, mostly remembered today thanks to Homer's epic poem about the Trojan War?

What rectangular military formation of spearmen with shields helped the ancient Greeks win battles like Marathon and Thermopylae?

Before he became an apostle, St. Paul was known as "Saul of" what Anatolian city?

What measure of a circle would you square and multiply by pi to find the area?

What's the "Kennection"?