Have we always had the custom of...

In the distant past, say before 4000 B.C., the human race didn’t have a system to keep track of time, so celebrating birthdays was a problem. Humans had to invent calendars first. Even after they did, for a long time only kings celebrated their birthdays because someone kept track of when they were born. No one recorded the births of common people. In Greek culture, the heads of important families celebrated their birthdays, but few others. The common practice today including cakes and birthday candles first became popular in the mid-1800s, shortly after the practice of sending Christmas greeting cards came into style.