Every occupation in medieval Europe had a patron saint. And each saint had a particular saint's day. The various guilds typically held festival celebrations on their saint's day. For example, St. Joseph was the patron of carpenters, St. Ivo of Kermartin was the patron of lawyers (later, along with Thomas More). Etc.
It might be interesting to include that information on the page for each occupation. Or would it be offensive to non-Christians?