The Latin East, born in the aftermath of the First Crusade (1095-1099), was ruled by a military, Catholic and Latin aristocracy, which claimed a social, cultural, economic and political superiority. In this work, I studied the practices of power of this dominant class : the lords deployed diverse actions and techniques to establish, impose, legitimate, and perpetuate their domination, during a long twelfth century (from the foundation of the Kingdom of Jerusalem to the arrival in Orient of Frederick II Hohenstaufen in Orient in 1229). These practices - ranging from the construction of castles to military service, from justice to marriages, and from council to lottery - structured the games of power and characterized the political nature of this aristocratic society. The Latin Orient is a rich field of study inasmuch the Latin lords, although they remained part of a Western cultural landscape, nevertheless knew how to adapt to local conditions. These were marked in particular by a very high ethnic and religious diversity, which led the lords to show a real legal and political inventiveness and borrow many practices from the Byzantine and Muslim worlds. In this peculiar society, an original political culture grew and evolved over the course of the century. It was characterized by an intense circulation of power, both real and symbolic, which flew over the whole seigneurial society.