Anania Shirakatsi (Ananias of Shirak) was an Armenian scientist and mathematician, famous there for authoring two important works, Geography and Cosmography and the Calendar, which tackled astronomy, meteorology, and geography.

He is considered the father of natural sciences in Armenia and his books, while readable to a lay audience, were also technical enough to be used as textbooks for centuries.   

He described the world as "being like an egg with a spherical yolk (the globe) surrounded by a layer of white (the atmosphere) and covered with a hard shell (the sky)" and wrote that "that the Milky Way is a mass of dense but faintly luminous stars and agreed with earlier philosophers that the moon was a dark body by nature whose only light was that which it reflected from the sun" and he described his education as that he “acquired a perfect knowledge of mathematics. In addition, I also learned a few elements of other sciences.”

Anania Shirakatsi's 1400th anniversay has been included in UNESCO's honorary list of anniversaries for 2012.    So why say happy birthday today?   Well, no one knows when he was actually born - or where, despite leaving an autobiography.   Various sources have it between 2010-2012 and one of the things he attempted to accomplish was getting the Armenian Apostolic Church to modify the Armenian calendar from a movable to fixed system.  He also did not think the seven day week, lunar month and solar year were all that great so his version had a cycle of 532 years.    It was never adopted but it was interesting and, since no one knows when he was actually born, I might as well make today Anania Shirakatsi day.

Anania Shirakatsi statue in front of the Matenadaran (Mashtots Institute of Ancient Manuscripts) in Yerevan, Armenia