Unlike his predecessor, who was something of an outsider to Vatican politics, Giovanni Cardinal Montini was a skilled administrator. Before his appointment as archbishop of Milan in 1954, Montini was a career diplomat in the Vatican's Secretariat of State under both Pius XII and John XXIII. When Pius XII died in 1958, Archbishop Montini was widely viewed as a possible successor but was passed over, perhaps because he was not yet a cardinal. He continued to serve John XXIII, who finally elevated him to the cardinalate, and was himself elected pope in 1963.
The postage stamps Vatican City changed dramatically during Paul VI's reign. The subjects commemorated became more internationalist in nature as opposed to focusing exclusively on church history and art. Multicolor printing techniques were more extensively used beginning in 1967, and watermarked paper was abandoned in 1972. Prior to 1970, all Vatican stamps had a limited period of validity (normally eighteen months for commemoratives and about five years for definitives). This practice ended in 1970, and all Vatican stamps issued since then have been valid for postage indefinitely. Near the end of the papacy, jumbo-size stamps and setenant issues began to appear with increasing regularity.