It was named thus because a sect of ancient French people on the river Seine, called the Parisians, meaning in the old French tongue "inhabitants of the edges and borders." This name is not derived from Paris, the name of a famous man, as some have claimed. This city is one of the most prosperous cities in the world and one of the greatest cities of the Franks now. It is the seat of the land of the French and the base of the kingdom of France, and the details of this will come later in its place. It is situated at forty-nine degrees and fifty minutes of northern latitude, meaning it is this far from the equator towards the north. As for its longitude, it varies. If we consider the meridian to which the French attribute the longitudes of all other places, which is the meridian drawn in their astronomical observations and which passes through Paris, then it is the beginning of longitudes according to the French, so its longitude would be zero. However, if we calculate it based on the meridian from which Ptolemy used to take longitudes, and which is still the beginning of longitudes for some places, such as the people of Flanders, which is the meridian of Algiers and the islands of the Moroccan Sea, then Paris was at approximately twenty degrees of eastern longitude. We will mention here how to determine the degrees of longitude and latitude of a place, and its benefit, even if it deviates from our purpose in this regard. We say: Know that the astronomers have clarified with evidence the sphericity of the Earth, and that it is not perfectly spherical. Then they made a representation of it and drew a picture of the Earth. To divide the Earth and facilitate its knowledge, they imagined meridians and parallel circles, an axis, and two poles, and drew them in their artificial representation. The equator of the terrestrial sphere is the line parallel to the axis of the celestial sphere, and its poles are the two poles, one of which is called