Caduceatores travel across Mythic Europe, delivering messages between magi and far-flung conventa. What are all these messages? They might contain questions, or invitations to some gathering, for example, or trade in vis or texts. However, such possibilities seldom offer enough routine messaging for members of Domus Merceris to spend much of their time traveling from conventum to conventum.

So, why might magi engage in regular correspondence with one another? Well, to exchange knowledge. This Saga Rule, based on an earlier essay published in a now-defunct Ars Magica fanzine, provides a worthwhile incentive for magi to engage in routine communication with each other.

Magi may engage in correspondence that can result in the gradual accumulation of experience. To do so, two or more magi must agree to exchange correspondence in a given subject (an Ability or Art). One magus begins the exchange by spending a week of time (which counts as a distraction from other activity, such as lab work or study) to author an initial message to the other magus. Once the other magus receives this message, he may allocate a week of time in some season to read & respond to the message. By doing so, he receives a single point of experience in the subject of correspondence.

A magus may only read & respond once in a given season, regardless of the amount of time available. The remainder of whatever time might be available is spent considering the content of the message and integrating whatever was learned into his existing knowledge of the subject.

A magus may, however, initiate correspondence with another magus more than once in a given season; each correspondence requries a week of time in the season. No immediate benefit is gained from this time, but it is necessary to begin a correspondence.

After a magus has read a message, and drafted a response, that message may be sent via Domus Merceris to the recipient, and once the response arrives, the recipient may read & respone in kind, receiving a single point of experience in the subject of correspondence.

A magus may engage in as many different exchanges as he wishes, but is limited to reading and responding to a single message in each season, and must spend a week of time doing so.

Some notes on common salutations and closings in Mythic Correspondence are described here.