St. Benedict Medal

I found this St. Benedict Medal up at South Pass City Wyoming. Can anyone tell me the age and metal content. Like I said it was found at South Pass City Wyoming near the Oregon Trail. I was told that it could be lost by a French Trapper since they were Catholic. I looked it up on internet and I believe it could be made in the1800 's. I also think it is bronze and could anyone tell me value of bronze. I have been trying to age the medal and don't know what the letter S stands for in Roman numerals.