Blessed Pope John XXIII was intended to be a placeholder pope-a compromise candidate acceptable to both the conservative and liberal factions in the College of Cardinals because he would not 'rock the boat.' On the contrary, he convened the Second Vatican Council (1962-65), which instigated widespread reforms. One of the last stamp issues of his papacy was a 1962 set of eight commemorating the Council's opening.
In many ways, the other stamps of John XXIII's reign elaborated the themes established under Pius XII. In particular, the persecution of the church behind the Iron Curtain continued to figure prominently. A 1959 set of two stamps depicts Prince St. Casimir of Lithuania and the cathedral at Vilnius, then under the thumb of the Soviet regime. Other series approached the theme more obliquely, through references to historical persecutions; these include stamps showing saints martyred by the Roman emperor Valerian (1959); the flight of Jesus, Mary, and Joseph into Egypt to escape Herod's murderous rampage through Judea (1960); and the execution of St. Paul under the emperor Nero (1961). The 1961 set depicting Pope Saint Leo The Great can also been seen as an allegory of the Church's defiance of communism. In 1452, when the fearsome Attila the Hun threatened to invade Italy, Pope Leo went out to meet him and saved Rome from destruction by convincing Attila to turn back.