1 Testone - Gregory XIII Simple shield

Gregory XIII is remembered chiefly for the 1582 calendar reform that bears his name — the Gregorian calendar replaced the Julian system that had drifted roughly ten days out of sync with the solar year, a correction with direct implications for the calculation of Easter. The Ancona mint operated under direct papal administration throughout his pontificate, one of several provincial mints the Camera Apostolica maintained to serve the Adriatic commercial corridor.

The MIR distinction between varieties 1204/1 and 1204/2 reflects subtle differences in the shield rendering across die pairs, not a chronological sequence.