The virile young god from the east was beloved of soldiers who worshipped him by the light of flaring torches in underground temples, where the blood of sacrificial animals soaked into the mud floor. The reconstruction of his rites includes the soundtrack of shuffling sandalled feet and voices chanting in Latin the names of the levels of initiates taken from graffiti on a temple in Rome: the god still guards many of his secrets.
“It was a mystery cult and its rites remain very well guarded mysteries. There is nothing written about what went on in the temples, no book of Mithras,” said Sophie Jackson, the lead archaeologist from the Museum of London Archaeology who has spent years working on the excavation and reconstruction.
https://www.theguardian.com/science/2017/nov/08/reconstructed-roman-temple-mithras-opens-public-bloomberg-hq#img-1
“It was a mystery cult and its rites remain very well guarded mysteries. There is nothing written about what went on in the temples, no book of Mithras,” said Sophie Jackson, the lead archaeologist from the Museum of London Archaeology who has spent years working on the excavation and reconstruction.
https://www.theguardian.com/science/2017/nov/08/reconstructed-roman-temple-mithras-opens-public-bloomberg-hq#img-1