An advocatus, or advocate, was generally a medieval term meaning "lawyer". The term was also used in continental Europe as the title of the lay lord charged with the protection and representation in secular matters of an abbey, known more fully as an advocatus ecclesiae.
The office is traceable as early as the beginning of the 5th century in the Roman Empire, the churches being allowed to choose defensores from the body of advocates to represent them in the courts. In the Frankish Kingdom, under the Merovingians, these lay representatives of the churches appear as agentes, defensores and advocati; and under the Carolingians it was made obligatory on bishops, abbots and abbesses to appoint such officials in every county where they held property. The office was not hereditary, the advocatus being chosen, either by the abbot alone, or by the abbot and bishop concurrently with the count. The same causes that led to the development of the feudal system also affected the advocatus. In times of confusion churches and abbeys needed not so much a legal representative as an armed protector, while as feudal immunities were conceded to the ecclesiastical foundations, these required a representative to defend their rights and to fulfill their secular obligations to the state, such as leading the ecclesiastical levies to war. A new class of advocatus thus arose, whose office, commonly rewarded by a grant of land, crystallized into a fief, which, like other fiefs, had by the beginning of the 11th century become hereditary.