Society and religious life in Gaul in the Late Antiquity, administrative and judicial documents in the Post-Roman era, law, socirty and economic activities in Merovingian times, government and political structure of Merovingian State, manor structure in the Touraine in the Eary Middle Ages, religious and cultural exchange between England ant the continent in the Early Middle Ages, regional histories in the Post-Roman Gaul, history of Saint-Martin abbey at Tours, world system until the end of first millennium AD, etc.

All through of my academic career and activities, I have been fascinated with so complex a problem which is expressed in the end of Roman world and the birth of European Middle Ages. We have more than two hundreds historical grounds to give for explaining the fall of Roman Emire, but social and ecomomic as well as religious upheaval as systemic change in the Roman State on the one hand and the creation of Barbarian statehood into which all of the surviving elements of Roman heritage must have converged on the other hand, are questions of crucial importance to be answered for our overall understanding of the fate of human races. All of my researche projects mentioned above has been concerned with those vast questions.