The Vatican as a city-state was officially established on February 11, 1929, through the Lateran Treaty between the Holy See and the Kingdom of Italy. However, the history of the Vatican as a religious and historical site dates back much further:
- By the end of the Roman Republic, the area known as Vatican Hill was a small plain on the banks of the Tiber River.
- In 37-41 AD, Emperor Caligula built the Circus Vaticanus on the site.
- Around 64 AD, Saint Peter was martyred and buried in a necropolis near the circus.
- In 324 AD, Emperor Constantine built the first St. Peter's Basilica over Saint Peter's tomb, marking the beginning of the Vatican as a Christian religious center.
- The original basilica lasted until the early 1500s when construction of the current St. Peter's Basilica began in 1506 under Pope Julius II and was completed in 1626.
In summary, while the Vatican City as a sovereign state was created in 1929, the Vatican's architectural and religious roots date back to the 4th century AD with the construction of the original St. Peter's Basilica and earlier Roman-era structures on Vatican Hill.
