Example image of eyePlorer eyePlorer map for 'Astronomical year numbering': Anno Domini Common Era Decimal Integer Negative and non-negative numbers Year zero Fred Espenak Gregorian calendar Jacques Cassini Julian calendar Simon Newcomb 0 (number) Epoch (astronomy) Astronomy Archaeology Before Present Dendrochronology Geology History 18th century Astronomer France Philippe de La Hire French language Latin Holocene calendar 1st century BC World population estimates Proleptic Gregorian calendar Proleptic Julian calendar Millennium Century Ecliptic Doomsday rule Julian day Calendar era