Zero Meridian (Prime Meridian)
The Zero Meridian, also known as the Prime Meridian, is the zero degree of Longitude that passes through Greenwich in London.
The Roman Prime Meridian
In Ptolemy's Geographia (c. 150 CE), the Roman Prime Meridian, also known as Zero Degrees Longitude, was based in the Canary Islands and centred on Mount Teide in Tenerife.
This meridian served as the reference point for longitude in the ancient Roman world long before the modern Greenwich standard was adopted.
Roman Astronomy and Ptolemy
The greatest Roman astronomer was Ptolemy (c. 90–168 CE), who produced a revolutionary star catalogue known as the Almagest. This work predicted the position of any planet at any time of day or night on any day of the year and identified 48 Constellations.
Legacy of Ptolemy’s Astronomical System
Despite modelling the Solar System with the Earth at the centre rather than the Sun, Ptolemy’s ideas dominated astronomy for nearly 1,400 years. His geocentric system remained authoritative until 1543 CE, when Copernicus introduced the heliocentric system, fundamentally changing humanity’s understanding of the cosmos.
Greenwich Prime Meridian