  a t and o map or o-t or t-o map (orbis terrarum, orb or circle of the lands; with the letter t inside an o), is a type of medieval world map, sometimes also called a beatine map or a beatus map because one of the earliest known representations of this sort is attributed to beatus of liÃ©bana, an 8th-century spanish monk. the map appeared in the prologue to his twelve books of commentaries on the apocalypse. ==history and description== the t-o map represents the physical world as first described by the 7th-century scholar isidore of seville in his etymologiae (chapter 14, de terra et partibus):  although isidore taught in the etymologiae that the earth was "round", his meaning was ambiguous and some writers think he referred to a disc-shaped earth. however, other writings by isidore make it clear that he considered the earth to be globular. indeed, the theory of a spherical earth had always been the prevailing assumption among the learned since at least aristotle, who had divided the spherical earth into zones of climate, with a frigid clime at the poles, a deadly torrid clime near the equator, and a mild and habitable temperate clime between the two. the t and o map is representing only the top-half of the spherical earth.michael livingston, [http://www.strangehorizons.com/2002/20020610/medieval_maps
Early_Middle_Ages Map_types