Time Measurement and Calendar Construction

30 days accepted according accurate actual adopted ancient appears arrangement astronomical Babylonian basis became beginning calculation called celebration century Chaldeans Chinese Christian civil clock commencement common complete considered construction contain count countries cycle divided divisions doin early earth Egypt Egyptian emperor equal equinox Europe February festival figure five fixed four given gives Greek Gregorian calendar Hebrews Hindu important India indicated influence intercalary intercalation intervals introduced January Julian calendar kings known later leap length lunar lunation luni-solar March marked mean measurement method month moon names natural night observed occurred origin period Persian planets position present proposed reckoning recorded reform relation religious Roman rule seasons seems setting sexagenary cycle signs solar solar calendar solstice stars summer Sunday tion tropical universal usually vernal equinox week winter Zodiac