The reply, “On the 15th Nisan,” conveyed nothing either to the Romans or to the Egyptians; it was intelligible to the Semites alone. Thus, where the Semitic Calendar was not understood, it was necessary to fix the day by some other method. In the choice of methods, the Church of Alexandria, and, most of all, the Church of Rome, took the lead. The simplest plan would have been to discover on which day of March or April the 15th Nisan had fallen in the year of Christ’s death, _i.e._ 782 U.C. But it was impossible to do this with certainty after a few decades had elapsed. Another starting-point had to be sought, and this was naturally given by the spring full moon, _i.e._ the full moon nearest to the vernal equinox, for the 15th Nisan must fall either on this full moon or thereabouts. Thus in Rome and Alexandria, all the principles which are in force at the present day were gradually adopted, _i.e._ Easter is to be celebrated on the Sunday after the full moon following the vernal equinox. There is evidence that this rule for determining the date of Easter was followed in Rome from the time of Pope Sixtus I., possibly even earlier. The further developments do not concern us here. Here and there in the West, there was a tendency to commemorate the death and resurrection of Christ on fixed days in the Julian Calendar—on the 25th and 27th of March, for example—but it never became general. For the most part, the data for the calculation of Easter were the same as those employed for calculating the Jewish passover; that is to say, the full moon on the one hand, and the vernal equinox on the other, Sunday being introduced as an additional factor in the calculation, since our Lord had risen on that day of the week. In this way the above rule was established, and so, in the date of Easter as determined at the present day, the variable Jewish lunar year has left a trace behind it, and, also, the connection in which Christianity stands to Judaism receives a practical expression deserving of being preserved to the end of time.[108] 4. _The Final Settlement of the date of Easter and the Attempts made to commemorate the day of the Month on which Christ died_ The manner in which the commemoration of our Lord’s passion and death admitted of being celebrated in agreement with the Jewish Calendar, is due to the minuteness with which the fourth Evangelist describes the events of Holy Week. On the 9th Nisan our Lord arrived at Bethania. The next day, the 10th, took place the triumphal entry into Jerusalem[109]—Palm Sunday. 11th Nisan, Monday. Curse pronounced on the barren fig-tree, and second, cleansing of the Temple. 12th Nisan, Tuesday. Conferences between our Lord and the Pharisees and Sadducees; the widow’s mite; attempts of the Greeks to see our Lord. 13th Nisan, Wednesday. Judas betrays our Lord to the Chief Priests. 14th Nisan, Thursday. The Last Supper and the Betrayal.