First-class sources

It wasn't on paper only that this lifelong project was intended to be "complete". Although the so-called "Western" astronomy, from Babylon and Egypt to Huygens and Cassini, through Greece, Rome and Alexandria, was central, it was only a part of a truly universal project. It was necessary to establish a real dialog between the European astronomical tradition and the other traditions which were almost completely unknown until that time. Such was the case of the Chinese tradition, for instance. But, fortunately, Jesuit missionaries had been working on it for almost a century.