The International Date Line

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     The Syrian prince and geographer-historian Isma‘il ibn ‘Ali ibn Mahmud ibn Muhammad ibn Taqi ad-Din ‘Umar ibn Shahanshah ibn Ayyub al Malik al Mu’ayyad ‘Imad ad-Din Abu ’l-Fida (1273 - 1331) in his Taqwin al-Buldan  described how a traveler, depending on his direction of travel, would either lose or gain a day at the completion of his circumnavigation of the globe.
     Erik de Put (Erycius Puteanus, 1574 - 1646) published a work in 1632 in which he argued for the adoption of a prime meridian running through Rome. The meridian opposite to that of Rome he named the Linea Archemerina and marked the line where the calendar date changed.
     Puteanus pointed out that in order to be useful a date line should pass only over water without crossing any land and he conceded that his date line would have to make an eastward excursion at the latitude of ‘New Albion’ in order to satisfy this condition. When the Prime Meridian was established at Greenwich in 1884, the 180th meridian was agreed as the place where the day changed. Over the years several changes were made where the line did cross land.
     New Zealand marked the beginning of the 21st century with a stamp which showed a map of the world with the sun crossing the International Date Line.

SCN 1628

     The time notation in the lower left corner, "3:59 NZST" indicates the time of the first sunrise of the new century on the Chatham Islands of New Zealand. To the right of the time notation is an emblem made up of a representation of the sun and a map of New Zealand.