The twelve Houses of Hermes fall into three groups, one of which is referred to as the True Lineages. This means that the members of these houses can trace their lineage all the way back to the founder of the House. It is not possible to join one of these houses after passing the gauntlet as a member of another house. The four houses that are considered true lineages are House Bonisagus, House Guernicus, House Mercere, and House Tremere.