Flemish cartographer and dealer in maps, books, and antiquities, who published the first modern atlas, Theatrum orbis terrarum (1570; Epitome of the Theater of the Worlde).

Trained as an engraver, Ortelius about 1554 set up his book and antiquary business. About 1560, under the influence of Gerardus Mercator, Ortelius became interested in mapmaking. Within a decade he compiled maps of the world on a heart-shaped projection (1564), of Egypt (1565), and of Asia (1567), as well as the first edition of the Theatrum, which contained 70 maps, derived from 87 authorities and engraved in a uniform style. Enlarged and kept up to date in successive editions until late 1612, the Theatrum appears to have been the most popular atlas of its time. He was appointed geographer to Philip II of Spain (1575). A facsimile of the Theatrum was published in 1964.