(M23) The practical inconvenience of a calendar which marked true time only once in about fifteen hundred years might be calmly borne by a submissive Oriental race like the ancient Egyptians, but it naturally proved a stumbling-block to the less patient temperament of their European conquerors. Accordingly in the reign of King Ptolemy III. Euergetes a decree was passed that henceforth the movable Egyptian year should be converted into a fixed solar year by the intercalation of one day at the end of every four years, “in order that the seasons may do their duty perpetually according to the present constitution of the world, and that it may not happen, through the shifting of the star by one day in four years, that some of the public festivals which are now held in the winter should ever be celebrated in the summer, and that other festivals now held in the summer should hereafter be celebrated in the winter, as has happened before, and must happen again if the year of three hundred and sixty-five days be retained.” The decree was passed in the year 239 or 238 B.C. by the high priests, scribes, and other dignitaries of the Egyptian church assembled in convocation at Canopus; but we cannot doubt that the measure, though it embodied native Egyptian science, was prompted by the king or his Macedonian advisers.(52) This sage attempt to reform the erratic calendar was not permanently successful. The change may indeed have been carried out during the reign of the king who instituted it, but it was abandoned by the year 196 B.C. at latest, as we learn from the celebrated inscription known as the Rosetta stone, in which a month of the Macedonian calendar is equated to the corresponding month of the movable Egyptian year.(53) And the testimony of Geminus, which I have cited, proves that in the following century the festivals were still revolving in the old style.