A patrician is the leader of one of the five major families in a merchant republic. The doge of the republic is elected from the five patricians, and the other 4 serve as his vassals.
Owners of 
The Republic DLC can play as patricians. Patricians have a number of unique events related to their status as powerful merchant lords and as leading families in a republic - they may gain or lose money from their businesses and they may involve themselves in multi-generational rivalries.
Each patrician:
- has a barony-level holding called a family palace which can't be lost or revoked.
- can also hold other landed titles, and may have cities and castles in their demesne without suffering the wrong holding type penalties.
- may hold titles below the level of their republic's doge: patricians in a kingdom-level serene republic may hold duchies, while patricians in a duke-tier republic may only rise to the level of counts.
- may have vassals of their own.
Patricians have a number of unique opportunities not available to the nobility:
- They can construct trade posts in any coastal province (including foreign ones) and can build contiguous trade zones that bring in a lot of money.
- They also have a "Seize Coastal City" Casus Belli which allows them to conquer a city in any county they have a trade post in.
- They can follow this up with a "Seize County" CB in the county where they own the town, although there is a range limit.
Patricians are limited in the number of trade posts they can build by the number of adult dynastic males in their court, by the building level of their family palace, and by the Trade Practice technology in the republic's capital. Patricians can also "steal" trade posts through plotting and warring with other patricians in their Republic.
As the head of a family, patricians are also responsible for supporting some of their relatives. All income of the family (from both taxes and trade) is divided into equal shares. The patrician gets 10 shares while every adult male of their dynasty in their court gets 1 share. This is usually offset by the contribution to the trade post limit and the fact that seniority succession means that the money of a patrician's relatives will ultimately end up in the possession of a patrician again.
Patricians are considered lower than barons for marriage purposes, and frequently have a hard time getting noble brides without paying a dowry. This bride price is equal to the prestige gained from marriage, so it increases according to the rank of the lady's relatives and her dynastic prestige. Also, ladies of a patrician dynasty cannot marry matrilineally.
A patrician inherits through agnatic seniority succession and this cannot be changed by normal means. However, the Patrician can use the "Designated Heir" honorary title to pick a dynastic heir outside of agnatic seniority. The normal agnatic seniority also skips landed nobles in the dynasty.
Patricians and vassal doges pay taxes at half the regular burgher tax rate.