Johannes Covens 1697-1774 & Cornelius Mortier (1699-1783)
Under Pieter Mortier an extensive publishing business was built up in Amsterdam and which, after his death, was subsequently taken over by his son, the above-named Cornelis. In 1721 Cornelis married the sister of Johannes Covens and in the same year he and Johannes entered into partnership as publishers under the name Covens and Mortier which, with its successors, became one of the most important firms in the Dutch map publishing business.
Their prolific Output over the years included reissues of general atlases by Sanson, Jaillot, Delisle, Visscher, de Wit (whose stock they acquired) and others (often with re-engraved maps), atlases of particular countries including Germany, England and Scotland and others in Europe, pocket atlases, town plans and, from about 1730 onwards, a series under the title Nieuwe Atlas, some consisting of as many as 900 maps by various cartographers and publishers. As there is no conformity about these volumes they were presumably made up to special order and only general details of publication can be quoted in a work of this size