Abraham Ortelius' Monumental work Theatrum Orbis Terrarum is regarded as the first atlas to appear. An atlas is defined in this instance as a uniform collection of map sheets of similar size, with sustaining text, compiled for the purpose of binding the sheets together to form a coherent book.

The reason why the texts on verso of the atlas maps written by one of the best studied cartographers, viz. Abraham Ortelius (1527-1598) of Antwerp in his Theatrum Orbis Terrarum of which the first edition appeared in 1570 have never been studied in the course of 450 years will probably remain an enigma. The research presented here tries to demonstrate that these texts contain many innovations in 16th century historical cartography. For this purpose, a sample of on verso texts as occurring on ten atlas maps from Ortelius' Theatrum atlas has been examined and translated into modern English.

Rarity is determined by two factors — the number of maps produced by the printer and the percentage of that number which have withstood the ravages of time. The number of copies printed is primarily determined by economic considerations. The printer will not produce more copies than can be sold within a reasonable period, otherwise investments — and paper was not a cheap commodity in the sixteenth century — are wasted. Survival is determined by a number of factors. The first is age. The older the map, the smaller its chances of survival. Secondly, the size. A wall map is particularly vulnerable due to its large size and will therefore deteriorate rapidly as can be seen in any geography classroom. The third is protection. A map bound in an atlas is stored as a book and thus protected by its binding. This increased the chance of survival. The fourth is appeal. In all periods of cartography some maps have a stronger appeal than others because of the information they give and their aesthetic value. Fifthly, there is accuracy. Maps which display outdated information tend to be discarded as soon as better information becomes available. This applies particularly to the separate maps of today such as town plans or motorway maps. Lastly, there is breaking. The cutting up of atlases to sell the maps separately has caused considerable loss, not immediately of the loose maps but of the bound volume.