There was a belief among the geographers of the Middle Ages that the length drawn by the geographical coordinates was the limit that God placed on the intelligence of people. Far from reality, these lines awaited great international prestige; States such as Spain, Ingland or the Netherlands convened contests with high rewards looking for the most effective method to define these measures, since geographic coordinates guarantee safer and more precise navigation and border delimitation.
Having its own meridian as a State was a sign of notoriety and diplomatic relevance. Spain, over the years, had several: Toledo, Madrid, Isla del Hierro, Mount Teide or the city of Salamanca. However, the Cádiz ship was during the 18th and 19th centuries the one with the greatest reference weight for the Spanish fleet.
In 1717, the Real Casa de la Contratación de Indias, an entity in charge of controlling trade and navigation with overseas territories, settled in Cádiz. It is the golden age of Spanish trade, and the city becomes one of the most important commercial epicenters in the world. In the same year, the first Academy of Marine Guards of the Navy was also created in Cádiz, the antecedent to the Naval Military School.
A series of events to which was added that in 1753 the Navy Astronomical Observatory was located in this city of the Bay. The Cadiz meridian was established as the reference for the navigation of the Spanish fleet; other nationalities also adopted it as their own. The notoriety and popularity of the city grew very fast in light of its meridian and its commercial flow.
However, at the end of the 19th century, the United States Government convened the Washington International Conference for the adoption of a Universal Prime Meridian. It was agreed to propose to the governments represented in Congress the adoption of the Greenwich Meridian as the Master Meridian of Longitudes.
Its acceptance as universal would be stated, especially at the beginning, but in 1907 the Greenwich Meridian was adopted as the prime meridian for naval use in Spain. Shortly after, the Minister of the Navy ordered the Directorate of Hydrography that all nautical charts use the Greenwich Meridian as the origin of longitudes. This same official provision ordered that the Nautical Almanac for 1910 be calculated using Greenwich, and not that of the Bay, as the reference meridian.
This is how the Meridian Zero of Cadiz went from prestige and the reference of the international fleet, to becoming a Lost Meridian.
