Did people in the dark ages know what year it was? Did the roman empire keep track of the date in a fairly accessible way? Basically when did the average person become able to answer the question what year is it.
There is evidence of prehistoric societies keeping track of time many thousands of years ago. Some of the earliest known writing deals with time.
For thousands of years societies have been keeping track of the date, though many times an elite group kept the calendar and told the masses when to plant their crops and when to celebrate festivals.
In ancient Rome dates were usually given as the year of the consulship of X and Y. But some scholars calculated the year that they thought that Rome was founded and expressed dates since the foundation of Rome AUC (Ab Urbis Conditatea). Emperor Philip the Arab celebrated the anniversary of the founding of Rome in 248 AD (1000 AUC).
The ancient Greeks often expressed dates by the year within an Olympiad, a 4 four year period between Olympic Games.
Anyone who made a contract to perform something or pay something by a specific date or periodically had to keep track of the date, and more and more people made such contracts as time went on.
The navigators in Magellan's ships kept careful track of time and when they arrived back in Spain they were shocked to find that their date was a day off (due to going around the world from east to west).
In short, beginning in prehistory, at least some people in every society have kept track of dates in some way or another, and throughout history more and more people have become more and more aware of the date and eventually even aware of the time of day.