When was the vaticon built?

Answer 1

The Vatican site was once the site of Caligula's Circus Maximus[later finished by Nero]. The obelisk in the centre of St Peters Square is its only visible remnant surviving today. Tradition holds that this is the same site where St Peter was crucified,and later buried. In 326 the Basilica of St Peter was built, then in the 5th century a palace was constructed near the Basilica by Pope Symmachus. This was the start of the collection of buildings that make up Vatican City.