Issued by Vatican City in 1969, this 50 Lire stamp commemorates the centenary of the First Vatican Council (Concilium Vaticanum I, 1869–1870). The design features the ornate papal coat of arms, surmounted by the triple tiara and crossed keys, against a rich blue background. The First Vatican Council was convened by Pope Pius IX, defining key doctrines including papal infallibility. This stamp is a notable item for collectors of religious, ecclesiastical, and Vatican philately, marking an important event in Church history.