It is more likely that they brought the lunar month with them, taking it roughly as 30 days (30 × 12 = 360), than that they began with such an erroneous notion of the true length of the solar year, seeing that in Egypt, above all countries in the world, owing to the regularity of the inundation, the true length could have been so easily determined, so soon as that regularity was recognised. We must not in these questions forget to put ourselves in the place of these pioneers of astronomy and civilisation; if we do this, we shall soon see how many difficulties were involved in determining the true length of such a cycle as a year, when not only modern appliances, but all just ideas too, were of necessity lacking.
Since 360 days do not represent the true length of the year, it is clear that any nation which uses such a year as that will find the seasons and festivals sweeping through the year. Further, such a year is absolutely useless for the agriculturist, or the gardener, because after a time the same month, to say nothing of the same day of the month, will not mean reaping-time, will not mean sowing-time, or anything else.
Still, it is right that I should state that all authorities are not agreed as to the use of this year of 360 days; at all events, during the times within our ken. Maspero[68] states:—
"Des observations nouvelles, faites sur le cours du soleil, décidèrent les astronomes à intercaler chaque année, après le douzième mois, et avant le premier jour de l'année suivante, cinq jours complémentaires, qu'on nomma les cinq jours en sus de l'année ou jours epagomènes (epacts). L'époque de ce changement était si ancienne que nous ne saurions lui assigner aucune date, et que les Egyptiens eux-mêmes l'avaient reportée jusque dans les temps mythiques antérieurs à l'avènement de Mini."
Ideler[69] is of the same opinion as Maspero:—
"I do not hesitate ... to declare that the existence of such a time cycle—used without reference to the course of the sun or moon simply for the sake of simple figures—is extremely doubtful to me."
Krall remarks (p. 17):—
"It is probable that the year of 360 days dates from the time before the immigration into the Nile valley, when the Egyptians were unguided by the regular recurrence of the Nile flood. In any case, this must soon have convinced the priests that the 360-days year did not agree with the facts. But it is well known to everybody familiar with these things how long a period may be required before such determinations are practically realised, especially with a people so conservative of ancient usages as the Egyptians."
And on this ground, apparently, he joins issue with the authorities already quoted:—
"The Egyptian monuments have contradicted Ideler in this respect. The trilingual inscription of Tanis testifies expressly that it has only 'later become usual to add the five epagomenes;' that, therefore, the year originally had 360 days, which were divided into twelve months of thirty days each."