It is probable that on the original Beatus map both the Four Sacred Rivers and the Ancestors of Mankind were depicted, as on the 'family' of maps that are associated with the Henry of Mainz map (Slides #215, 225, 226). The four rivers of Paradise are a reference to Genesis ii, 11-14. The first three rivers are usually identified with the Indus or Ganges, the Nile, and the Tigris. Also, in the Beatus maps, there is no clear evidence of a dependence on the T-O design so dominant during this period of cartography. The horizontal line dividing Europe from Asia is pushed up towards the top, and thus deflected from the actual middle (only on the Osma map is there an exception).
Beatus seems to have followed Isidore in his limiting of Africa to this side of the Equator, this was also the practice of many of the classical geographers such as Cicero, Pliny and Mela. Although he never displayed it on his maps, Isidore conceded the probable existence of the southern Antipodes, and, based upon a single sentence or two from his pen, all of the Beatus copies, except the Paris III map of 1250, portrayed an unknown continent south of Africa and the Indian Ocean. Even the Paris III map, however, gives a relic of the 'Australian Continent' by indicating, in a corner, the Skiapod, a shadow-footed monster whom the Osma map of 1203 shows in the 'Southern Land'; this last was doubtless the original position.
As to the appearance of the circumambient fish and boats, these fish occur in every Beatus derivative except the Turin map; the boats are found on the following copies: St. Sever, Ashburnham, Valladolid, Gerona, and the Paris III map of the 13th century.
In the original Beatus design, as in most medieval maps, the Mare Rubrum [Red Sea] appears to have been colored according to its name; but on the Paris III map of 1250, the Valladolid, and the Ashburnham, this tint is confined in a more modern sense to just the Arabian and Persian Gulfs; both of these gulfs on the Ashburnham and Valladolid examples are depicted rather like the symbols used for denoting mountains than seas, in red color; in the Madrid map only the Arabian Gulf is red in color; on the London copy the mountain-like appearance is even more pronounced; on the Gerona, Turin and Paris III maps, both gulfs are tinted with the traditional hue of the sea. On every Beatus map Professor Miller recognizes a trace of the original legends in this area. The Black Sea, the Sea of Azov and the Caspian Sea occur on the St. Sever and on the Osma maps, but are wanting on all maps of the Valcavado group. The distortion of the Mediterranean Sea fares no better on these maps than on the other cartographical works of the early Middle Ages.
The rivers of the world are more realistically portrayed on the best copies of Beatus, the St. Sever and the Osma; on the other examples, and especially on the Paris III map of 1250, the representation of the streams may sometimes be used for restoring the probable contents of the original Beatus map. Thus, apparently the original map contained no Spanish rivers, but marked the Rhine, the Rhone, the Danube, the Euphrates, the Tigris, the Jordan, the Nile with its delta, and certain affluents of the Caspian.
Where all of the copies agree, we may suppose that we are dealing with material from the original Beatus prototype; and, fortunately, the coincidences between and among all of the derivatives are so numerous that we can, from these alone, form a pretty detailed picture of the fundamental draft. Therefore, to summarize, the original Beatus design may have presented a schematically drawn, basically oval map designed to promote the spread of the Christian Faith and may have contained such features as a 'Southern Land' or Antipodes, a circumfluent ocean filled with fish and possibly boats, colored seas with some being depicted as mountains, at least the seven aforementioned rivers, and an ample distribution of pictorial displays and textual legends. The text of some of the longer legends gives a fairly good idea of the anthropological outlook of Beatus, his copyists and the medieval European. The following is such an example:
Albania, so called from the whiteness of its people, and color of their hair, extended from the east, close to the Caspian Sea and the shore of the Northern Ocean [into which the Caspian was believed to flow] to the Maeotid Lakes [Sea of Azov], through desert regions where the dogs were so strong and fierce that they could kill lions. Hyrcania, so called from the Hyrcanian Wood [a confusion with the Hercinia Sylva of Germany] which lay 'under Scythia', was full of tigers, panthers, and pards. Many races lived here and in Scythia, among them cannibals and blood-drinkers. Scythia, stretching from the extreme east and the Seric Ocean, to the Caspian Sea (at the setting sun) and southward to the ridge of Caucasus, abounded in gold and gems, in the best emeralds and in the most pure crystal; but all of these treasures were guarded by Gryphons, and no man could approach thereunto. Armenia, between the Taurus and the Caucasus, and between Cappadocia and the Caspian, was divided into two parts, the 'Greater' and the 'less', and contained the source of the Tigris. Arabia, the land of incense and perfumes, of myrrh and cinnamon, of the phoenix and sardonyx, was also called Saba, from the son of Chus. The Dead Sea, so named because it produced nothing living, and received nothing from the race of living things, was in length 780 stadia and in breadth 150 [this attempt at measurement is a very unusual feature on a medieval map, and shows a curious, if inaccurate, precision, or spirit of inquiry (the figures that are given are twice too great). Beatus also gives measurements, in Roman miles, for the islands of Britain, Corsica, Sardinia and Taprobane.] India, containing many peoples and tongues, men of dark color, great elephants and precious products, such as gems, ivory, aromatics, ebony, cinnamon and pepper, was also famous for its parrots, dragons and its one-horned beasts [rhinoceros]. It was amazingly fertile, with crops twice a year; and among its gems were diamonds, pearls, burning carbuncles, and beryls; it also possessed mountains stored with gold, and guarded by dragons and monstrous men. Among its islands were Chryse [the Malay Peninsula] and Argyre, the isles of gold and silver and Taprobane, which lay far to the south, was divided by a river, was only in part inhabited by men, had ten cities and was full of jewels and elephants. Ethiopia, stretching to the borders of Egypt, abounded in races of diverse color and monstrous form. It possessed multitudes of wild beasts and serpents, precious stones, cinnamon and balsam. The Nile was said by some authors to rise far from Mount Atlas, and thereafter to be speedily lost in the sands. But soon it emerged from the desert, poured itself out into a vast lake, and thence flowed to the Eastern Ocean, through Ethiopia. Here, again, bending to the left, it descended upon upon Egypt .
Of these legends on the Beatus maps, most of them are to be found in the writings of Isidore, but some have, ultimately, far more ancient origin. Thus the notice of Parthia plainly refers to a time before the Persian revival of 226 A.D.; while the dimensions of the Dead Sea and Lake Gennesaret, in stadia, also prove a considerable antiquity, perhaps back to a source at the time of Pliny. The legends referring to the Hellespont and the Bosphorus correspond, in substance, with the descriptions of these areas found in the writings of not only Pliny, but also Mela and Solinus; the measurements of the greater islands (i.e., Britain), in Roman miles, seem to be reminiscent of an imperial Itinerary.
A general stemma [genealogy] for the large Beatus maps which shows the lineage of the extant Beatus manuscripts containing full-page maps is provided in Harley's History of Cartography, Volume One (adapted from Klein).