Well, it's sort of hard to answer. There have always been doomsday cults that think the world will end in X year. There always will be. However, the modern calender (Anno Domini) wasn't invented until the 6th or 7th C. Even then, it didn't get widespread use immediately. Portugal didn't use it until the 15th C. Eastern European countries didn't use it until the 18th C.

Then there is the problem of when the new year is. To us, it's Jan 1. However, most people know that the Chinese New Year is later. Before the 16th and 17th C, the New Year could be celebrated as early as August 29/30 or as late as the end of March. It isn't until the 20th C that everyone came together and acknowledge Jan 1 as the New Year.

Also, there is the Julian/Georgian calendar issue. Both are still in play, really. The Orthodox churches use the Juilian while the Roman Catholic and many protestant churches use the Georgian. It makes a difference as to what day it is.

Now, with all that confusion, add in that the vast majority of people are uneducated- therefore, numbering systems are pretty meaningless to them. Farmers - of which there were MANY- cared about the seasons, not what year it was. They had to know when to plant, what to plant, when to harvest, ect.