Finding a mysterious medal is always exciting, especially if you know there’s history behind it. This OP found a 4ct gold cross with the markings “H I S V” on the corners and “all for one one for all” etched on the back. Quite intriguing, indeed.
According to some online sleuths, this is the symbol of The Masonic and Military Order of the Red Cross of Constantine. It is an order of Freemasonry that operates in more than 40 countries around the world. Maybe it belonged to a member of the organization. The real question is how and where did the OP find it.