T and O map

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), also known as an Isidoran map, is a type of early world map that represents the physical world as first described by the 7th-century scholar Isidore of Seville (c. 560–636) in his De Natura Rerum and later his Etymologiae (c. 625)

Although not included in the original Isidorian maps, a later manuscript added the names of Noah's sons (Sem, Iafeth and Cham) for each of the three continents (see Biblical terminology for race).

More detailed later maps with equivalent orientation are sometimes described as a "Beatine map" after the Beatus map because one of the earliest known representations of this sort is attributed to Beatus of Liébana, an 8th-century Spanish monk, in the prologue to his Commentary on the Apocalypse.