Dating time in b c
The problem became--how do you deal with a fraction of a day?
Those fractions built up over time: eventually, the calendar that you were relying on to schedule events and tell you when to plant became off by several days: a disaster.
These early astronomers marked time by the only way possible: by learning the motions of celestial objects such as the sun, moon, and stars.
These earliest calendars were developed all over the world, by hunter-gatherers whose lives depended on knowing when and where the next meal was coming from.
The earliest Babylonian calendar reckoned the year to be 360 days long--that's why we have 360 degrees in a circle, 60 minutes to an hour, 60 seconds to the minute.
Neolithic calendars must include the stone circles and megalithic monuments of Europe and elsewhere, some of which mark the important solar events such as solstices and equinoxes.
The first surviving use of the BC/AD convention was by the Carthaginian bishop Victor of Tunnuna [died AD 570).
, a history of the world begun by Christian bishops in the 2nd century AD.
BC/AD was also used by the British monk the "Venerable Bede", who wrote over a century after Victor's death.
The BC/AD convention was probably established as early as the first or second century AD, if not widely used until much later.