The Ripuarian Franks and the Chatti raid across the middle Rhine frontier during the first quarter of the fifth century.

The Franks, taking advantage of the overstrained Roman defenses, solidify their hold on present Belgium and assume permanent control of the lands immediately west of the middle Rhine River.

The legendary Pharamond is said to have led the Franks across the Rhine, and to have recolonized the old town of Duisburg (Germany).

Duisburg, chartered in 1129, is a thriving commercial center established in Roman times in western Germany, located on the east bank of the Rhine River at its junction with the Ruhr River and the Rhine-Herne Canal.

Gerardus Mercator, married (to Barbara Schellkens) with six children, moves in 1552 at age forty to the Duchy of Cleves to become a mapmaker and lecturer at the University of Duisburg.

Once here, he becomes a well-known figure, and assists the duke in establishing a grammar school by helping to design its curriculum.

After establishing a cartographic workshop and engaging his own engravers, he returns to his main interest.

He publishes a superb six-panel map of Europe in 1554.

Gerardus Mercator produces a map of the British Isles in 1564.

His famous navigation chart of the same year introduces the map projection bearing his name, with its parallels and meridians at right angles.

Mercator first uses his cylindrical projection on his world map of 1569.

He begins work on his great Atlas, in which he seeks to describe the creation and history of the world.