Easter therefore varies between 4 April and 8 May in the Gregorian calendar (the Julian calendar is no longer used as the civil calendar of the countries where Eastern Christian traditions predominate).Also, because the Julian "full moon" is always several days after the astronomical full moon, the eastern Easter is often later, relative to the visible moon's phases, than western Easter.Paul states, "Get rid of the old yeast that you may be a new batch without yeast—as you really are.For Christ, our Passover lamb, has been sacrificed"; One interpretation of the Gospel of John is that Jesus, as the Passover lamb, was crucified at roughly the same time as the Passover lambs were being slain in the temple, on the afternoon of Nisan 14.
Perhaps the earliest extant primary source referring to Easter is a mid-2nd-century Paschal homily attributed to Melito of Sardis, which characterizes the celebration as a well-established one.
This interpretation, however, is inconsistent with the chronology in the Synoptic Gospels.
It assumes that text literally translated "the preparation of the passover" in John refers to Nisan 14 (Preparation Day for the Passover) and not necessarily to Yom Shishi (Friday, Preparation Day for the Passover week Sabbath) Jewish Christians, the first to celebrate the resurrection of Jesus, timed the observance in relation to Passover.
While martyrs' days (usually the individual dates of martyrdom) were celebrated on fixed dates in the local solar calendar, the date of Easter was fixed by means of the local Jewish lunisolar calendar.
This is consistent with the celebration of Easter having entered Christianity during its earliest, Jewish period, but does not leave the question free of doubt.