Medieval European cartography reflected the arrest and decline in geographical knowledge following the collapse of the Roman world. Ptolemy's Geographia remained known only to Byzantine scholars, and thence it came to influence the early students of Arabic geography. Only in one type of medieval Christian European map does there survive, in very simple form, some concept of Greek geography. The hemispheric maps of Macrobius, drawn in Spain and later reproduced in the works of the Venerable Bede, Lambert of St. Omer and others, show the habitable world of the northern hemisphere and the uninhabited world of the southern, marked with climatic-zones derived from Ptolemy's clima, and, unlike many other medieval maps, they are oriented with North at the top.

Macrobius was a late Roman neoplatonic grammarian and philosopher who wrote several eclectic works that were much read in the Middle Ages. His Expositio In Somnium Scipionis ex Cicerone [Commentary on the Dream of Scipio by Cicero] is an extract from the sixth book of Cicero's De Republica. Macrobius' commentary on this work includes geographical theories which were to some extent based upon Ptolemy, but with certain differences. Macrobius preferred Eratosthenes' more accurate calculation for the circumference of the earth (252,000 stadia =25,000 miles, vice Ptolemy's 180,000 stadia =22,500 miles). With its postulate of a stationary round earth at the center of the universe and its contention that the environmental sea, variously called the Atlantic, the Great Sea and the Ocean, which 'in spite of these big names, is quite small', it is definitely in the Ptolemaic tradition. However, it departs from that tradition in making this ocean the boundary, in every direction, of the inhabited earth, giving it the shape of a lozenge, narrow at the extremes and wide in the middle, and in positing the existence of three other landmasses corresponding to the oikoumene [inhabited world], in the remaining quarters of the earth. In his territorial division, Macrobius adopts the conventional five zones, and, while maintaining the existence of an Antipodean race of men, he also maintains that there is no way by which knowledge of them can be obtained. He, like his near contemporary Martianus Capella, proposed that this inhabited world, which lay entirely north of the Equator, was surrounded by an ocean, which also filled the impassable equatorial zone, a theory which can in no way be reconciled with Ptolemy's catalogue of places in the Southern Hemisphere.

According to an essay by Michael Andrews, the majority of medieval world maps of the Hemispherical Family are constructed in accordance with what is known as the oceanic theory, attributed to a 5th century B.C. Greek philosopher, Crates of Mallos, which recognized two oceanic streams (Slide #113 ). The 'true' ocean encircled the sphere equatorially, while the popularly accepted ocean which passed through the poles was regarded as subsidiary. These two streams, flowing at right angles to one another, divided the world into four equal landmasses. Some groups of maps, however, give no indication of any equatorial ocean nor in consequence of any quadripartite division.

Andrews further divides the Hemispherical Family of medieval maps into two main branches: the Oceanic or Quadripartite Division and the Non-Oceanic or Non-Quadripartite Division. The maps belonging to the first division, which, to judge by the numerous examples remaining to us, was by far the most popular in medieval times, is further classified as Simple and Zone.

The Simple Genus includes maps such as those in the Liber Floridus of Lambert of St. Omer and some in the works of William of Conches, which depict the whole hemisphere bisected by the equatorial ocean, but do not indicate any division by zones. The northern habitable parts in these maps are often divided in tripartite fashion, but sometimes have no formal divisions (Slides #217, #225.1).

In the Zone Genus the hemisphere is divided into five zones: Those climate-zones at the two poles, uninhabitable because of the cold; that at the Equator, uninhabitable because of the torrid heat; and the northern and southern temperate zones which were habitable, although only 'our' climate - the northern temperate zone - was included in the known world. Around the landmasses flowed an ocean whose currents Macrobius described as running from the equatorial zone, upwards to the north and downwards to the south, while the equatorial ocean flows west. As can be seen on some exemplary maps, the north and south polar bays, where the waters flowing in different directions met twice daily with a great shock, and in turning back gave rise to the tidal phenomena. Examples of various Species of this Genus are to be found mainly in the Commentarius in Somnium Scipionis of Macrobius, the Philosophia and Dragmaticon of William of Conches, and less frequently in other works. In the Macrobian maps, the Cratesian scheme is usually more fully illustrated by the inclusion of inscriptions dealing with the oceanic tides.

In the Somnium Scipionis of de Republica and elsewhere, Cicero makes clear his belief in the theory of a southern continent or Antipodes. Macrobius' 5th century commentary carries further the statement of Cicero concerning the habitable character of this southern zone, specifically known as the Antichthon. Macrobius affirms that it is reason alone that permits us to assume its habitable character, for the intervening torrid zone prevents us from ever knowing what the truth of that matter may be.

The story of the origin and the persistence of the belief in that continent, of the controversies which grew out of that belief, of the centuries of exploration in search of the elusive shores of the Terra Australis, is one of the most curiously interesting in the record of human thought and action. The maps in which the theory found delineation are of much more than incidental interest in the present discussion. The symmetry and logic contained in the theory that if the earth was indeed a sphere (an idea also proposed by Greek philosophers as early as the 5th century B.C.) then, for the equilibrium of that sphere to be maintained, it was a necessity of the laws of physics that there exist landmasses in the south and west to act as "counter-weights" to the masses of the north and east which formed the oikoumene or inhabited world of Europe, Northern Africa and Asia. This theory of the Antipodes, therefore, has haunted geographical thinkers with a persistence bridging not centuries but millenniums. The concept was continually debated in 'print', often vehemently, by the Church Faithful such as Cosmas Indicopleustes (Slide #202 ) and the influential and respected scholar St. Isidore of Seville; and expounded graphically on maps by Macrobius, Beatus, Lambert of St. Omer, the Venerable Bede, William of Conches, and others, for more than 2,000 years.

The long controversy was settled, so far as the western Antipodes were concerned, when America was discovered and its great extent revealed on maps. The desire to discover the southern antipodes, or the Antichthon, became thereafter one of the impelling motives of exploration and cartography, as can be evidenced in the work of such people as the late 18th century English geographer, Alexander Dalrymple and the continual efforts at Antarctic exploration that has persisted to the present day.

The map illustrated above is characteristic of the later medieval versions of the Macrobian world-picture, although some examples preserve richer nomenclature. This example displays a roughly drawn land mass to the left, representing Europe: Temperata nostra, above which is the northern frigid zone: Septentrionalis frigida inhabitabilis. The enclosed water represents the Mediterranean Sea, the Black Sea, etc. To the right is a vaguely formed Asia with the words Mare Caspian, set down at random, below which are areas intended to depict Arabia and India. The scribe has mislocated the caption for the Red Sea and Indian Ocean: Mare Rubrum Mare Indicum. Africa, intercepted by the equatorial Perusta zona just below the Mediterranean edge, finally tapers off against the impassable stream which cuts the known world off from the bowl-shaped continent at the south of the circle, Temparata Antipodum, and below, the Frigida Australis Inhabitabilis. In the ocean to the left of Europe are two large islands labelled Horcades Insulae [the Orkneys]. Other islands and land masses are reduced, in Cicero's words, to the position of mere 'specks' upon the water.

As mentioned earlier, the orientation is relatively unique for medieval mappaemundi, in that Macrobian maps are oriented to the north, vice the east, where Jerusalem was often mistakenly reflected as the center of the world. It is doubtful how soon the Macrobius plans were altered by medieval copyists into the uncertain orientation which we find in other manuscripts. It is certain, however, that Macrobius himself definitely put north at the top, for in one place he states that the upper temperate zone was inhabited by men of our race. In one of these climate/zone-maps in particular (Slide #201E), a distinction is drawn between the 'domestic folk' of the same temperate zone and the 'wild men' of the woods, who inhabited arctic and torrid lands. Not all Macrobian maps display only five zones, some depict seven zones or belts; the division of the world into climate-zones or belts can be traced back to Marinus of Tyre and Ptolemy (Slide #119).

The work of Macrobius experienced tremendous popularity throughout the time period loosely termed the Middle Ages, even considering the inherent distributive limitations of hand-copied manuscripts. By the 12th century the work of Macrobius had become standard textbook material in the schools, eight centuries after his initial work. Marcel Destombes has recorded about 150 manuscripts dating from 1200 to 1500 A.D., two-thirds of which preserve copies of the basic map design illustrating Macrobius' theories as expounded in parts of the first and second Books of his Commentary. As alluded to earlier, these maps also had extensive influence on the medieval mappaemundi of others, from the Venerable Bede in the 8th century, to Lambert of Liege, William of Conches and Honorius of Autun in the 12th century, and a less direct, though discernible impact on the cartography later developed by Arab scholars. Printed copies of the Macrobius text and derivative maps can be found at least well into the 15th century, one reprint appearing as late as 1500.