Flag of the Vatican

Vatican City's flag is square, with an aspect ratio of 1:1. It is vertically divided into two equal fields of yellow (hoist side) and white. The white field bears the coat of arms of Vatican City, consisting of the Papal Tiara above two crossed keys: one gold and one silver, tied with a red cord.

Yellow and white represent the gold and silver keys of Saint Peter, respectively. These keys, bound together, symbolize the power to bind and loose on Earth and in Heaven, as bestowed upon Saint Peter by Jesus Christ. The Papal Tiara represents the Pope's authority as the supreme pontiff of the Catholic Church, signifying his spiritual leadership.

The current flag of Vatican City was officially adopted on June 7, 1929, the year the Lateran Treaty with Italy established Vatican City as an independent state. This design superseded previous flags used by the Papal States, which varied over time. The adoption of this flag coincided with the reign of Pope Pius XI and the resolution of the Roman Question, solidifying the Vatican's sovereignty.