20 Lire The Keys of the Town

San Marino issued a series of themed coinage throughout the late 1970s focused on civic and institutional subjects, part of a broader annual minting program the republic used to sustain collector interest and generate revenue — a financial strategy that became increasingly central to San Marino's economy as tourism and philatelic/numismatic exports grew. The 1979 program fell under the "The Arts" series umbrella.

Bronzital was the standard alloy for Italian 20 Lire pieces of the period, keeping San Marino's issues visually and materially consistent with the Italian coinage circulating alongside them under the 1862 monetary convention framework still loosely governing the relationship.