Not all Christians celebrate Easter on this day. The Eastern Orthodox Easter this year falls on April 12.
The “Eastern” Orthodox Churches still use the Julian calendar which was in general use in Europe and Northern Africa until 1582, when Pope Gregory XIII promulgated the Gregorian calendar.
In 2017 both the branches of Christianity will celebrate Easter on April 16.
According to Encyclopedia Britannica. “The Orthodox tradition prohibits Easter from being celebrated before or at the same time as Passover.”
There will be another posting later today.