Covens and Mortier (1721 - c. 1862). The Amsterdam publishing firm of Covens and Mortier was the successor to the extensive publishing empire built by Frenchman Pierre Mortier (1661 - 1711). Upon Mortier's death in 1711 his firm was taken over by his son, Cornelius Mortier (1699 - 1783). Cornelius married the sister of Johannes Covens (1697 - 1774) in 1821 and, partnering with his brother in law, established the Covens and Mortier firm. Under the Covens and Mortier imprint, Cornelius and Pierre republished the works of the great 17th and early 18th century Dutch and French cartographers De L'Isle, Allard, Jansson, De Wit, and Ottens among others. They quickly became one of the largest and most prolific Dutch publishing concerns of the 18th century. The firm and its successors published thousands of maps over a 120 year period from 1721 to the mid-1800s. During their long lifespan the Covens and Mortier firm published as Covens and Mortier (1721-1778), J. Covens and Son (1778 - 94) and Mortier, Covens and Son (1794 - c. 1862).