Dion Cassius, in the third century, represents the week as universally spread in his times, and considers it a recent invention which he attributes to the Egyptians; meaning thereby, doubtless, the astrologers of the Alexandrian school, at that time very eager to spread the abstract speculations of Plato and Pythagoras. If the names of the days of the week were derived from the planets, the sun and moon, as is easy to see, it is not so clear how they came to have their present order. The original order in which they were supposed to be placed in the various heavens that supported them according to their distance from the earth was thus:--Saturn, Jupiter, Mars, the Sun, Venus, Mercury, the Moon. One supposition is that each hour of the day was sacred to one of these, and that each day was named from the god that presided over the first hours. Now, as seven goes three times into twenty-four, and leaves three over, it is plain that if Saturn began the first hour of Saturday, the next day would begin with the planet three further on in the series, which would bring us to the Sun for Sunday, three more would bring us next day to the Moon for Monday, and so to Mars for Tuesday, to Mercury for Wednesday, to Jupiter for Thursday, to Venus for Friday, and so round again to Saturn for Saturday. The same method is illustrated by putting the symbols in order round the circumference of a circle, and joining them by lines to the one most opposite, following always in the same order as in the following figure. We arrive in this way at the order of the days of the week. [Illustration: FIG. 58.] All the nations who have adopted the week have not kept to the same names for them, but have varied them according to taste. Thus Sunday was changed by the Christian Church to the "Lord's Day," a name it still partially retains among ourselves, but which is the regular name among several continental nations, including the corrupted _Dimanche_ of the French. The four middle days have also been very largely changed, as they have been among ourselves and most northern nations to commemorate the names of the great Scandinavian gods Tuesco, Woden, Thor, and Friga. This change was no doubt due to the old mythology of the Druids being amalgamated with the new method of collecting the days into weeks. We give below a general table of the names of the days of the week in several different languages.