Gerardus Mercator in the context of "Abraham Ortelius"

A prime meridian is an arbitrarily chosen meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. On a spheroid, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great ellipse. This divides the body (e.g. Earth) into two hemispheres: the Eastern Hemisphere and the Western Hemisphere (for an east-west notational system). For Earth's prime meridian, various conventions have been used or advocated in different regions throughout history. Earth's current international standard prime meridian is the IERS Reference Meridian. It is derived, but differs slightly, from the Greenwich Meridian, the previous standard.

Longitudes for the Earth and Moon are measured from their prime meridian (at 0°) to 180° east and west. For all other Solar System bodies, longitude is measured from 0° (their prime meridian) to 360°. West longitudes are used if the rotation of the body is prograde (or 'direct', like Earth), meaning that its direction of rotation is the same as that of its orbit. East longitudes are used if the rotation is retrograde.

Gemma Frisius (/ˈfrɪziəs/; born Jemme Reinerszoon; December 9, 1508 – May 25, 1555) was a Dutch physician, mathematician, cartographer, philosopher, and instrument maker. He created important globes, improved the mathematical instruments of his day and applied mathematics in new ways to surveying and navigation. Gemma's rings, an astronomical instrument, are named after him. Along with Gerardus Mercator and Abraham Ortelius, Frisius is often considered one of the founders of the Netherlandish school of cartography, and significantly helped lay the foundations for the school's golden age (approximately 1570s–1670s).

The 16th century begins with the Julian year 1501 (MDI) and ends with either the Julian or the Gregorian year 1600 (MDC) (depending on the reckoning used; the Gregorian calendar introduced a lapse of 10 days in October 1582). The Habsburg Spanish Empire, Portuguese Empire, Ottoman Empire, Safavid Persia, Mughal India and Ming China were the most powerful and hegemonic states.

The Renaissance in Italy and Europe saw the emergence of important artists, authors and scientists, and led to the foundation of important subjects which include accounting and political science. Copernicus proposed the heliocentric universe, which was met with strong resistance, and Tycho Brahe refuted the theory of celestial spheres through observational measurement of the 1572 appearance of a Milky Way supernova. These events directly challenged the long-held notion of an immutable universe supported by Ptolemy and Aristotle, and led to major revolutions in astronomy and science. Galileo Galilei became a champion of the new sciences, invented the first thermometer and made substantial contributions in the fields of physics and astronomy, becoming a major figure in the Scientific Revolution in Europe.

The Mercator projection (/mərˈkeɪtər/) is a conformal cylindrical map projection first presented by Flemish geographer and mapmaker Gerardus Mercator in 1569. In the 18th century, it became the standard map projection for navigation due to its property of representing rhumb lines as straight lines. When applied to world maps, the Mercator projection inflates the size of lands the farther they are from the equator. Therefore, landmasses such as Greenland and Antarctica appear far larger than they actually are relative to landmasses near the equator. Nowadays the Mercator projection is widely used because, aside from marine navigation, it is well suited for internet web maps.

In Greek mythology, the Hyperboreans (Ancient Greek: ὑπερβόρε(ι)οι, romanized: hyperbóre(i)oi, pronounced [hyperbóre(ː)oi̯]; Latin: Hyperborei) were a mythical people who lived in the far northern part of the known world. Their name appears to derive from the Greek ὑπέρ Βορέᾱ, "beyond Boreas" (the god of the north wind). Some scholars prefer a derivation from ὑπερφέρω (hyperpherō, "to carry over").

Despite their location in an otherwise frigid part of the world, the Hyperboreans were believed to inhabit a sunny, temperate, and divinely blessed land. In many versions of the story, they lived north of the Riphean Mountains, which shielded them from the effects of the cold north wind. The oldest myths portray them as the favorites of Apollo, and some ancient Greek writers regarded the Hyperboreans as the mythical founders of Apollo's shrines at Delos and Delphi.

The Renaissance in the Low Countries was a cultural period in the Northern Renaissance that took place in around the 16th century in the Low Countries (corresponding to modern-day Belgium, the Netherlands and French Flanders).

Culture in the Low Countries at the end of the 15th century was influenced by the Italian Renaissance, through trade via Bruges, which made Flanders wealthy. Its nobles commissioned artists who became known across Europe. In science, the anatomist Andreas Vesalius led the way; in cartography, Gerardus Mercator's map assisted explorers and navigators. In art, Dutch and Flemish Renaissance painting went from the strange work of Hieronymus Bosch to the everyday life of Pieter Brueghel the Elder. In architecture, music and literature too, the culture of the Low Countries moved into the Renaissance style.

The Mercator world map of 1569 is titled Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendate Accommodata (Renaissance Latin for "New and more complete representation of the terrestrial globe properly adapted for use in navigation"). The title shows that Gerardus Mercator aimed to present contemporary knowledge of the geography of the world and at the same time 'correct' the chart to be more useful to sailors. This 'correction', whereby constant bearing sailing courses on the sphere (rhumb lines) are mapped to straight lines on the plane map, characterizes the Mercator projection. While the map's geography has been superseded by modern knowledge, its projection proved to be one of the most significant advances in the history of cartography, inspiring the 19th century map historian Adolf Nordenskiöld to write "The master of Rupelmonde stands unsurpassed in the history of cartography since the time of Ptolemy." The projection heralded a new era in the evolution of navigation maps and charts and it is still their basis.

The map is inscribed with a great deal of text. The framed map legends (or cartouches) cover a wide variety of topics: a dedication to his patron and a copyright statement; discussions of rhumb lines; great circles and distances; comments on some of the major rivers; accounts of fictitious geography of the north pole and the southern continent. The full Latin texts and English translations of all the legends are given below. Other minor texts are sprinkled about the map. They cover such topics as the magnetic poles, the prime meridian, navigational features, minor geographical details, the voyages of discovery and myths of giants and cannibals. These minor texts are also given below.