This (wearable!) ring was made at the tail end of the Middle Ages and the dawn of the Renaissance, the 14th - 15th c. A short list of what was happening in Europe then: the Crusades were being fought in the Holy Land, Gothic art and architecture was at its height, and the university system as we know it was being born. Europe's identity and culture was being formed through literature, religion, and the arts (including jewelry!) The age of sea exploration was yet to come. A survivor of all this change: the jewel you're looking at. It's a small miracle, a time traveler.