When was the circus maximus in rome built?

There is not a precise date. The fifth king of Rome, Tarquinius Priscus, who was said to have ruled from 616 to 579 BC, was said to have built some seating for the aristocracy. It was just the start of its development and the seating covered only a small part of the track. The development of the Circus Maximus took place over several centuries. The seating was completed to cover most of the track in the 40s BC by Julius Caesar. Monumental additions to it were made by Augustus (ruled 27 BC to 14 AD). Despite the wooden seating being the cause of many fires, it was replaced by stone seating in the time of Trajan (ruled 98 to 117 BC).