Captain: Character must have Per 20+, Int 20+, Chr 20+, and have prior experience as a veteran, captain, knight, schulz, courtier, manorial lord, or bishop.
Abbot: Character must be a male with at least Per 25+, Int 20+, Chr 20+, and Religion 15+. Character must have either a) spent the last 5 years as a noble heir, courtier, manorial lord, priest, abbot or bishop; or B) spent the last 10 years as either a monk and/or professor. A female abbot (abbess) is possible.
Bishop: Character must be a male with at least Per 25+, Int 25+, Chr 25+. In addition he must have spent either a) the last 5 years as an abbot or bishop, or B) the last 10 years as a courtier manorial lord, and/or priest.
Monk/Nun: Any character can enter a monastery except those who already have sufficient religous status, education or experience. A character can do this only once per lifetime.
Knight: Character must have a virtue of 16+ and either a) be a noble of age 20+; B) have just finished an occupation as a captain, courtier, noble heir, abbot, or bishop; or c) have any experience as a manorial lord or knight.
EDIT: Those

smilies were meant to be "b," but the forum insists on changing them. Oh, well.