Depicts a detail from the portrait of Saint Marinus by late 19th-century artist Emilio Retrosi, encircled by the twelve stars of Europe. In a semicircle to his left is the country name. In a similar fashion to his right are the date and mintmark (R). Engraver's and designer's initials are below.

Saint Marinus was the founder of a chapel and monastery, in 301, from where the world's oldest surviving republic, San Marino, grew. Tradition holds that he was a stonemason by trade who came from the island of Rab, on the other side of the Adriatic Sea (in what is now part of modern Croatia), fleeing persecution for his Christian beliefs in the Diocletianic Persecution. Still known only by the single name Marinus (lit. of the sea), he became a Deacon, and was ordained by Gaudentius, the Bishop of Rimini; later, he was recognised and accused by an insane woman of being her estranged husband, so he quickly fled to Monte Titano to build a chapel-monastery and live as a hermit. There he built a chapel and monastery. Marinus was canonised as a saint, and later, the State of San Marino grew up from the centre created by the monastery.

According to legend, he died in the winter of 366 and his last words were: "Relinquo vos liberos ab utroque homine" ("I leave you free from both men"). This somewhat mysterious phrase is most likely to refer to the two "men" from whose oppressive power Saint Marinus had decided to separate himself, becoming a hermit on Mount Titano: respectively the Emperor and the Pope. This affirmation of freedom (first and foremost fiscal franchise) from both the Empire and the Papal States, however legendary, has always been the inspiration of the tiny republic.

Designer: Arno Ludwig
Engraver: Uliana Pernazza

A geographical map of Western Europe spans the outer ring and inner core on the left side of the coin.

12 stars are located on the left side of the outer ring, with six stars atop the map of Europe and six stars below it; six vertical stripes cut across the inner core of the coin, visually connecting the upper and lower star segments.

Luc Luycx, a designer at the Royal Belgian Mint, designed the Euro’s common reverse; his initials, LL, are seen on the right side of the design, just under the “0” in “50.”