WWI German Helmets For Sale and other collectibles from WWI

British Map France

What did the Portuguese use as their Prime Meridian before the 1884 Meridian conference?

Prior to the 1884 adoption of the Greenwich Meridian as the worldwide Prime Meridian, many countries employed prime meridians that were tied to a location of national importance. For instance, in France it was the line of longitude that went through the Paris Observatory (before that it was Ferro Island, part of the Canary Islands). In Britain, the Greenwich Observatory was the standard for British mapping.

Things changed after the sun never set on the British Empire. And sun dials were always accurate.