Marinus of Tyre

Geographer, Mathematician (c.70 – c.130)

Marinus of Tyre was the greatest geographer of the 1^st century and the founder of mathematical geography. He exerted enormous influence on world geography up until the Renaissance. His work, which unfortunately does not survive on its own, was incorporated into Ptolemy’s Geographia in 150, making Marinus’ works available to the world. He is the inventor of the equirectangular projection, a map projection used in navigation.

He was born in Tyrus and lived in Rhodes. He was also a cartographer and a navigation specialist. He compiled a map with cylindrical projection of the entire known world at the time, with great accuracy, described the northern part of Europe and introduced the concept of meridional parts in navigation. This map was the basis of the Mercatorian projection, usurped by Gerhard Mercator. These projections are used in navigation today.

He was the first to devise a system of navigation maps. He established the Canary Islands as the first meridian for the beginning of the measurement of the geographic longitude of the Earth. He named it the Meridian of the Fortunate Isles. He established the meridian that crossed Gibraltar and Rhodes as the beginning for measuring the geographic latitude. In this way, he created the coordinate system where one could locate his position on the map based on the longitude and latitude. Furthermore, he divided the globe into 15 meridians of time and divided the globe’s latitude into 7 zones.

He was a proponent of the geocentric system and accepted Poseidonius’ estimation of the latitude of Rhodes (32.400 km, while in reality 32.000). He calculated the Earth’s circumference as 33.300 km using a system of oblique triangles which he invented. This system is still used today in navigation. In addition, Marinus formulated the use of biogeographic data. Marinus had a particular interest in meteorology. He was the first to come up with the most scientifically correct theory on air formation and flow. The name Antarctica was coined by him.

Marinus’ works were later collected and summarized by Ptolemy in his book Geographia. Ptolemy’s purpose for doing so was to correct some of Marinus’ mistakes and because his works had almost eclipsed. Ptolemy’s admiration for Marinus is evident from the fact that he uses his works as his guide. The first book of Ptolemy’s Geographia is entirely dedicated to Marinus and includes Marinus’ books Geographia and Correction of Geographic Tables. The book was translated into Arabic in the 9^th century and into Latin in 1406. Marinus’ map was used by Greek Christopher Colombus in 1492, redesigned by Paolo Toscanelli, for his travels across the Atlantic in 1492. Sadly, even though his work was the most important one in geography for centuries, this giant teacher of Geography was overshadowed by Ptolemy.

Bibliography

1. Georgakopoulos, Konstantinos. Ancient Greek Scientists. Georgiades: Athens, 1995. Print.
2. “Marinos o Tyrios”. Helios Encyclopaedic Dictionary. Passas, I. Athens, 1946. Print.