CHAPTER SEVEN WHAT IS GEO–ECCLESIOLOGY: DEFINING ELEMENTS APPLIED TO LATE ANTIQUITY (FOURTH–SIXTH CENTURIES) * PHILIPPE BLAUDEAU When I was working on my thesis twenty years ago, encouraged by my supervisor, Prof. Jean-Michel Carrié, I began to ask some new questions on the subject of the relations between the sees of Alexandria and Constantinople from 451 to 491. This very early Christian period has a particularly complex history, and the subject was a major challenge. Though it had been much studied and the problem itself much discussed, despite the quality of the research conducted in the modern era, from the Magdeburg Centuries on, or perhaps because of how it was treated, it did not seem to me to account for the exact nature of the conflict. I also wanted to develop a new working concept, geo–ecclesiology, which would give a better idea of the importance and significance of this quarrel. At the time I defined it as follows: The clash concerns rival systems, and it has three features: the doctrine of the imperial Church, time and space (Empire). Also, to better study the characteristics and functioning of these competing models, we propose the following process of interpretation: it is to distinguish the territorial logics and strategies implemented in order to gain pre-eminence in the imperial Church. The categories of systemic geography, geopolitics mainly, make such a study possible. 1 If it provides useful descriptive concepts such as foreland and hinterland, orbit, sphere of influence, or hot spot, this discipline invites us especially to study by analogy geographical spaces of permanent or durable presence, and areas of intervention. In short, it serves * The English text has been revised by Richard Bates with the financial support of Giunta Centrale degli Studi Storici (GCSS). 1 Our thinking was first stimulated by reading Dollfuss and Knafou 1990.