The image of the Tower has a very rich iconography that goes back to the late medieval times and reaches up to the 18th century. World maps and navigation charts are a most interesting legacy worth analysing as it provides us with a very suggestive view of this particular time. Besides, the fact that it has been used as a lighthouse for so many centuries accounts for this very noticeable presence in portulanos first and later in the navigation charts that were used by seamen to sail the seas.

In the High Middle Ages, the cosmographic tradition of the ancient world is lost and with it the concern for scientific rigour and a new type of map arises in Mozarabic Spain. It provides a legendary and symbolic approach to the world known. It is within this context that the world maps associated to beatos appear. These are codices which go back to the 10th and 13th centuries and which include the Comentarios al Apocalipsis attributed to Beato de Liébana. In this context, the world map illustrates the lands to evangelize and the distribution of these lands among the apostles. All the maps that have survived seem to stem from a single model, hence the coincidences among them.

Following Isidore’ approach, these are oriented maps, i.e., orient or the east is the cardinal point at the upper part of the map, and at the centre of it is where Paradise is located. It is clearly identifiable from the iconography used: almost invariably, Adam and Eve, the tree and the Serpent. Although this is not always so, it is often the case that the four rivers that rise from Paradise and that flow into the peripheral sea are drawn. Their names were Tigris, Euphrates, Gihon and Phison. Asia is placed on the upper part of the map and is separated from the other two continents by great courses of water from South to North: the River Nile, the River Hellespont, the Black Sea, the Sea of Azov and the Don River. At the bottom of the map, to the right is Africa and to the left is Europe, separated by tongue of water which is the Mediterranean Sea.

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