1.Why is not Easter on the same date every year like Christmas for instance?
in the 4th century it was decided that Easter would fall after the first full moon following the vernal or spring equinox.(The equinox is a day in the year on which daytime and night-time are of equal length).This happens twice a year ,once in spring and once in autumn.
We know from the New Testament that Jesus death and rssurection happened around the time of the Jewish feast of passover.According to Matthew, Mark and Lukes Gospels, the last meal jesus shared with his disciples was a passsover meal,while johns gospel says that jesus died on the feast of passover itself.in those days the jews celebrated passover on the 14th day of the first month,in accordance to the bible commands(see Lev 23;5, Num28;16 and Josh5;11).
The months of the Jewish calendar each began at new moon,so the 14th day would the day of the full moon. The first month,Nisan,was the month that began from the spring new moon.In other words, the Passover was celebrated on the first full moon following the vernal equinox and was ttherefore a moveable feast.
Early sources tell us that this very soon led to Christians in different parts of the world celebrating Easter on different dates. As early as the end of the 2nd century , some churches were celebrating Easter on the day of passover itself,whether it was Sunday or not,while others would celebrate it on the Sunday that followed it.By the end of 4th century there were f1our different methods of calculating the date of Easter.In the year 325, the council of Nicaea attempted to bring in unified solution that would retain the link with the date of passover as celebrated in Jesus time.Eventually,therefore,Easters date was established as moveable.