A title is a prefix or suffix added to someone's name in certain contexts. It may signify rank, or that the holder occupies a special position.
The most important titles are the landed titles, of which there are five ranks. These five ranks are usually termed baron, count, duke, king, and emperor. Only holders of count, duke, king and emperor-ranked landed titles are playable in Crusader Kings II.
There are also titles bestowed upon members of a count, duke, king, or emperor's council. These are usually termed chancellor, marshal, steward, spymaster, and court chaplain. Council members can be given tasks to carry out by their liege. Council members may be holders of lower-ranked landed titles who are vassals of their liege, or they may be unlanded characters in their liege's court.
There are also honorary titles which can be bestowed upon any vassal or courtier. These titles have no responsibilities, but will make the honoree like the bestower more (or less in the case of some humilitaing titles).
A list of minor titles follows. Some of these are honorary titles, and some of them are titles which are automatically granted to relatives of rulers and other important figures in the realm.
Keeper of the King's Swans
Master of the Horse
Master of the Hunt
Master of the Blade
Master of the Bow