Our protagonist John and his friends worship Mithra, a dangerous practice in an officially Christian court and one meaning they must worship in secret.

The links below provide background information on their religion as well as providing an overview of scholarly discussion of Mithraism in general.

The Mysteries of Mithra by Franz Cumont (1903}

Ostia Mithraea

Essay on Mithraism by Alison B. Griffith, Ecole Initiative

Mithras in the Encyclopaedia Britannica (1911)

Mithraism in the Catholic Encyclopaedia (1911)

German website on the cult of Mithra

Father Bianchi's Tale by R. H. Benson deals with Mithraic presence in church -- includes a brief mention of beliefs. Can be read online in collection titled A Mirror of Shalott by Robert Hugh Benson

Overview of Mithraism

Feature on Mithraism in Archaeology Magazine

Mithran Sanctuary Discovered in France

Essay on a Mithraic ritual by G. R. S. Mead

Mythraic Myths: Mary writes about what ancient misrepresentations about the Mithraic religion can teach us about religious misapprehensions today.

"Mithraeum of Colored Marbles" Romans worshipped Mithra and perhaps other gods in this former tavern converted into an elaborate mithraeum in Ostia, Italy.

Representations of Mithra:

Mithra statue

Carving of Mithra

Photo of Mithra © Marie-Lan Nguyen / Wikimedia Commons