1 Testone - Gregory XIII NVNQVAM DEFICIET

Gregory XIII is remembered almost exclusively for the calendar reform of 1582 — the Gregorian calendar replacing the Julian, correcting a ten-day drift accumulated since the Council of Nicaea. That reform required a papal bull, international negotiation, and the erasure of October 4–15 from existence across Catholic Europe. The testone was being struck in the thick of it, making this a coin of a pontificate defined by one of the most consequential administrative acts in the history of the Western world.

The motto NVNQVAM DEFICIET — "it shall never fail" — refers to papal faith, not the calendar, though the irony is there for the taking.