To Observe but Never Interfere.
The Talamasca is an organization mostly of witches, only a few vampires strewn in, dedicated completely to gathering information on anything they consider supernatural. No one knows their origins, not even the oldest members. The only known information about their history is the fact that their immense wealth was acquired through the Knights Templar.
The Talamasca is a very orderly gathering of scholars and highly dedicated to their cause. Rarely are rules broken, so when such an event does occur they are usually taken straight to the head of the organization, David Talbot.
The dwelling place of all Talamasca members is a castle by the name of Lorwich, known most commonly as the motherhouse, which sits right outside of the Osiris City gates. Here there are thousand of rooms, many offices, a grand banquet hall, and possibly the most extensive library ever established. Underground are thousand of archives containing some of the most detailed information gathered about vampires, witches, spirits, and anything else related to the supernatural, of which only the older and higher-up members are allowed access to.
All of the more important documents, however, are written in Latin, as are any written and occasionally verbal messages exchanged between members. Everything else is strictly English, the standard language spoken in the motherhouse for the sake of simplicity.
Again, let me stress that the only purpose of the Talamasca is to gather information. Interference is forbidden, though at times personal feelings are mixed in and the rules are inevitably broken.