The Order of Hermes is a fictional mystical group of wizards in the role-playing game Ars Magica by Atlas Games, set in Mythic Europe.
History
The Order of Hermes was founded by the wizards Trianoma and Bonisagus. Trianoma had the desire to unite the disparate Magi of Europe into a single group, who could learn from one another. She did not know how to accomplish this goal until she met Bonisagus. He had created a consistent theory of magic which would allow magi to share information, using a common frame of reference. Also, he had invented the ritual Parma Magica, a personal, protective, magical shield. Having Parma Magica would allow magi to meet face to face without fear of magical attack. Trianoma became Bonisagus' student, learned his theory and the Parma, then traveled throughout Europe recruiting other wizards. Eleven Magi joined her. Bonisagus and the eleven Magi established twelve Houses in a fellowship called the Hermetic Order of Hermes. The Order quickly recruited like-minded wizards, teaching the protective Parma Magica to Magi, who would take the Order's Oath of mutual cooperation. The wizards who refused to take the Oath were not taught the Parma Magica. Instead, they were hunted down and destroyed.
Houses
Every member of the Order belongs to one of the twelve Houses. The Houses were established by and named after Bonisagus and eleven of the twelve other Founders. Each House is led by a Primus (Latin = "the first", female Prima, general plural Primi). The Primi's authority and duties vary greatly between the Houses, ranging from absolute authority (House Tremere) to mere representation (House Verditius). The Primus lives in the domus magna (Latin = "Great House"), the headquarters of each House.
Bonisagus, Guernicus, Mercere, and Tremere Houses are the True Lineages. This means that each Magus was taught by a Magus of that House, and that master-apprentice relationship goes back to their founding Magus. These Houses are the backbone of the Order of Hermes. Houses Bjornær, Criamon, Merinita, and Verditius are the Mystery Cults of the Order. They are groups of Magi who have been initiated into at least one of their household's Mysteries. Ex Miscellanea, Flambeau, Jerbiton, and Tytalus are social Houses. These Magi are brought together by shared interests, common philosophies, and camaraderie.