I have mentioned that Mithras slaying the primordial bull is part of the Mithras cult, and that many altars in the mithraea show this scene. Below is a particularly beautiful Mithras altar from the museum at the Limes fort Osterburken in Germany.
Mithras altar stone, Osterburken
Scenes from Mithras' life and worship are depicted around the central scene of the tauroctony, the slaying of the bull.
Since the Mithras cult was especially popular among soldiers, there have been mithraea
near most Roman forts, though not all have been discovered yet. The Saalburg had one as well as Osterburken. The exact location of the mithraeum
of the latter is not known because the altar stone was discovered in the 19th century and taken to a museum before systematic diggings could take place. The whole first Osterburken excavation must have been a rather disorderly mess, and part of the fort is today covered by houses.
Closeup of the tauroctony
The figures to the left and right are Cautes and Cautopates, Mithras' helpers. I haven't yet figured out their exact role in the ritus, but they are in most tauroctony scenes, and even have figures of their own sometimes, as displayed in the Saalburg museum (post to come).
Osterburken managed to keep the altar stone which is today on display in the new museum that was built to cover the baths of the vicus
. Just well - the Römisch-Germanisches Nationalmuseum Mainz doesn't need to get everything
Mithras Slaying the Bull, York Museum
This stone has been found in York, together with other proof for the existence of a mithraeum
York, known in Roman times as Eboracum, was the administrative and military center of northern Britain, and people from all over the Empire brought their religions with them. Besides Mithras and Iupiter Optimus Maximus, the Roman State god, there was an alter dedicated to the Celtic Mother Godess popular in the Rhine area and several others. Often those foreign gods would be aligned with the Roman pantheon so that for example the British god Nodens became the same as Mars. The Roman Empire granted freedom of religion as long as the people also participated in the cult of the deified emperors.
Here's the last of the Mithras pics in my collection: Mithras as sun charioteer. There isn't acutally much left of him, but three out of the four horses are still in pretty good shape.
Mithras driving the Sun Chariot, Saalburg Museum
There are two motives that maybe stand for some sort of resurrection mythos connected to Mithras, his role as sun charioteer, and an iconographic motive that shows him dining with another god (Apoll?). I think this second motive may have been a later addition, because in the original mythos, Mithras is not connected with other gods of the Persian pantheon.
It's all very mysterious, but people - especially men - seem to be attracted to that sort of community; just look at the popularity of the Masons in the 18th/19th centuries. Initiation rites, grades of membership, secrets ... they got all that, too. Though I can't detect a direct historical connection between both.