In 1436, a simple inventory note revealed the identity of a remarkable jewel: a sapphire ring once belonging to Duke Ernest the Iron (1377–1424 CE). This elegant piece of jewelry is more than just a precious ornament—it is the oldest object in the medieval treasures of the House of Habsburg that can be unequivocally attributed to a specific individual. Its survival bridges history, connecting us directly to a powerful ruler whose descendants would go on to shape European politics for centuries. While countless treasures of the Middle Ages remain anonymous, this sapphire ring carries with it a name, a lineage, and a story that highlights the continuity of dynastic heritage. As such, it is both a personal relic of Duke Ernest and a symbolic artifact of Habsburg legacy, making it an extraordinary link between medieval nobility and enduring imperial tradition.