The history of Fort La Présentation is presented interwoven with the 18th century struggle between France and Great Britain. At stake was the domination of world trade and the political and military influence protecting it.  The double vocation--religious and military--of the fort-mission complex is investigated and its influence on the planning, construction and the selection of its location is discussed.  The evolution of the principle of the separation of two communities--European and autochthon--living inside quasi-independent fortified compounds, located side by side, is investigated.  The conclusion reached is that the politico-military aspect of the fort-mission complex of La Présentation was the main one and that its religious role, no matter how successful it was, served only as a cover-up.