The Mohammedan week is that of Judaism and Eastern Christianity, and was taken over bodily from one or the other of these religions. Sunday is the “first” day, and so in order to Thursday. Friday is “the meeting,” when one prays at the mosque, but labors before and after, if one wishes. And Saturday is “the Sabbath,” though of course without its Jewish prescriptions and restrictions. The Arabs have spread this form of the week far into Africa.
But the planetary week of Babylonian-Greek-Egyptian-Syrian origin spread east as well as west and north and south. It never became so charged with religious meaning nor so definitely established as a civil and economic institution in Asia as in Europe, but it was used astronomically, calendrically, and in divination. By the fifth century, it had been introduced into India. For a time after the tenth century, it was more used in dating than among European nations. Again “translations” of the god names of the planets were made: Brihaspati was Jupiter, and Brihaspati-vara Thursday.
From India, the week spread north into Tibet, east to the Indo-Chinese countries, and southeast to the Malay Peninsula, Sumatra, and Java. In the former lands, it was employed calendrically; among the Malaysians, rather astrologically, and has been largely superseded by the Mohammedan form. Even China acquired some slight acquaintance with the week as a period of seven days allotted to the planetary bodies and initiated by the day of Mit, that is, Mithra, the Persian sun god, although the average Chinaman knows nothing of the days of the week nor any periodic rest from labor.
127. Summary of the Diffusion
This history of the week is one of the striking instances of institutional diffusion. An ancient west Asiatic mystic valuation or magical cult of the number seven led on the one hand to an observance of taboo days, on the other to an association with the earliest astronomical knowledge, polytheistic worship, and divination. A European people learned the combination and built on it for further scientific progress, only to have this gain utilized for new playing by the astrologers. The planetary week, the creation of these mathematical diviners, was reintroduced into Europe and became connected with the calendar and civil life. Christianity recontributed the old idea of regularly recurring holy or taboo days. Mohammedanism took over this concept along with the period, but without the polytheistic and astrological elements. Eastern Asia, on the other hand, was chiefly interested in the latter. With us, the significance is becoming increasingly economic. Names have changed again and again, but their very variations evidence their equivalence. In about three thousand years from its first beginnings and half as many from its definitive establishment, the institution of the week by 1492 had spread over all the earth except the peripheral tracts of Asia and Africa and the peripheral continents of Oceania and America.
128. Month-thirds and Market Weeks
Contrasting with this single diffusion of the seven-day week is the independent development in several parts of the world of other periods, marked either by sacred or secularly unlucky days or by markets or by divisions of the lunar month.
For instance, a ten-day week, having reference to the beginning, middle, and end of the lunation, was more or less reckoned with in ancient Egypt; ancient Greece; parts of modern central Africa; China, Japan, and Indo-China; and Polynesia. No historic connections are known between the custom in these regions; its official and religious associations are everywhere slender, and intervening nations either employ other periods or none at all. It looks, therefore, as if these might be cases of true parallelism, although in that event an American occurrence might also be expected and its absence seems in need of explanation. Moreover there is nothing very important about this reckoning; it is essentially a description of a natural event, and the only thing distinctive is its being threefold. If an institution as precise and artificial as our planetary week had been independently originated more than once, the fact would be more significant.
Regular market days among agricultural peoples have frequently led to a reckoning of time superficially resembling the week. Thus, in central Africa, south of the sphere of Islamic influences, markets are observed by a considerable number of tribes. Most frequently these come at four day intervals. Some tribes shorten the period to three days or lengthen it to five. Six, eight, and ten day periods appear to be merely doublings. The fairly compact distribution of this African market week points to a single origin.