Definitely a cool ring! Looks like it has been a mascot for a number of things- with schools and fraternal involved- those are usual suspects for having a signet ring made. My guess would be with the Shriners made overseas. Some American GIs in Germany and other occupied areas had souvenir signets with their fraternal organizations in the cartouche. I have seen a handmade Masonic symbol made on an North African theatre piece before. Stamp is interesting looks like definitely a European or German design with a German silver stamp with the word foreign. Maybe ordered or a powar export mark? All just guesses here- but that ring is great. Hope you wear it around for luck!