The first Easter, according to calendar maker Dionysius Exiguus, occurred on March 25, in 31 A.D.
By the fifth century, people had two different methods of figuring out the date of Easter. A major Christian holiday, they really wanted to calculate the right day to celebrate. Then a scholar that worked old records, Dionysius Exiguus took on the task. He decided to use the two methods as calculations and figure out one way to pinpoint Easter. People have used his method for centuries even though current historians say he calculated wrong. Still, thanks to him we have the calculations that give us the date of Easter each year on the calendar.