Born in 1888, he completed his thesis on
Nicephorus Gregoras (a biography in 1926, and his edited correspondence in 1927), and succeeded his teacher
Charles Diehl in the seat of
Byzantine studies at the
Sorbonne in 1934, which he held until his retirement in 1958. His chief interest was in the late Byzantine period (1204–1453), particularly the
Palaiologan period, and his main areas of research were the history of the
Great Palace of Constantinople, and of the offices, dignities, and administrative apparatus of the Byzantine state. ==Works==