Example image of eyePlorer eyePlorer map for 'Proleptic Julian calendar': Julian calendar Proleptic 1582 Proleptic Gregorian calendar Bede Year zero Astronomical year numbering Ab urbe condita Julian day October 7 September 6 James Ussher Battle of Halys (585 BC) Chronology Nabonassar Rata Die Ussher chronology French Republican Calendar 0 (number) Callippic cycle 32nd century BC Callippus List of retronyms Proleptic calendar Doomsday rule Dating Creation Hindu units of measurement Hipparchus Calendar era Battle of Marathon Hebrew calendar Hindu calendar