The International Prime Meridian Conference, Washington, October 1984

Extract

By the middle of the nineteenth century, there were over a dozen different initial meridians for longitude on navigational charts, and a much greater number in use for time-reckoning. The need for a single internationally agreed meridian was recognised in the resolutions of the first International Geographical Congress held in Antwerp in 1871. They proposed that the meridian through Greenwich should be adopted, recognizing that this was already the choice of the vast majority of users, and linked this with a second resolution recommending the adoption of the metric system. This was partly a recognition of the intrinsic merits of the metric system, and partly as a concession to the French as compensation for the adoption of Greenwich rather than Paris. Although not widely used, the Paris meridian had some claim to consideration since the observatory through which it passed had been in existence several years before that at Greenwich.