Traditions of coloring eggs goes back much farther than most people realize. There have even been decorated and carved ostrich eggs excavated in Africa that date back nearly 60,000 years.
As a Christian practice, it began in Mesopotamia when the first Christians stained eggs with red coloring to symbolize the blood of Christ nearly 2000 years ago. But this isn't just a "tradition." The Christian Church officially adopted the practice in the early 1600's as an actual ritual.
Of course, in America today, although there is still a great deal of religious meaning behind colored Easter Eggs, they are also widely known as a fun family activity associated with the Easter Bunny, who began making his rounds in the 18th century.