Yeah, that would appear to explain it. But what about the origin of the idea of the creation of the world in 7 days in Genesis and the 7th day being dedicated to God?
This originated from Chaldean astrology: the Chaldeans, whose self-name
Khashd was eroded to
Khald when they migrated from the Caucasus (their language is difficult, and we know little of it, but it is definitely not Indo-European, perhaps akin to Georgian, whose self-name is
Khalt), had the idea of a
strict seven-day week. The quarter-phase week is usually seven days, but sometimes an eighth day must be skipped: the lunar month always has at least 29, and needs a 30th day slightly more often than not; the ancient calendar (first attested in a text from Sargon of Akkad c. 2300 BC but the idea goes back to deep prehistory) starts the month with day 1 when the crescent is just visible after sundown, count through day 7 when the half-moon should appear, then days 1 through 7 after half, and a skipped day at full moon (the 15th of the month, when religious feasts were typically scheduled), then days 1 through 7 after full with 7-after-full also a special day when the waning half should appear (22nd of the month), then days 1 through 7 after waning half where 7-after-waning (29th of the month) was called in Akkadian
biqquru "day of watching" because at sunset one would visually check whether the crescent came back (making it the 1st of the next month) or not yet (so that a 30th day had to be left out of the cycle).
The strict seven-day week means that the quarter-phase, instead of falling always on the last day of the week, slips around from one position to the next, once or twice every lunar cycle. The days were divided by the Chaldeans into 24 hours, instead of the older habit of only 8 "watches", and each hour named for a planet, in order of the planets' speed of motion Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon; each day then was named for its starting hour, giving the order Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn. The Genesis creation has:
"light" created on the day of the Sun (no explanation necessary);
the separation of heavens from earth on the day of the Moon (the Moon, as the lowest planet, was thought to hold up all the heavens;
Atlas in Greek is from Semitic
Etrach from Khashdic
Etrash "moon");
the separation of land from sea on the day of Mars (the "war" between land and sea was the primordial fight in older Mideastern creation myths; the word rendered "ocean" or "the deep" in Genesis is Hebrew
Tehom cognate to Babylonian
Tiamat, the monster of the ocean defeated by Marduk in their version of the primordial-war story);
the astrological signs and the calendar-rhythm of the seasons created on the day of Mercury (that planet was associated to
Ea or
Enki, patron god of scribes, astrologers, and other intelligentsia);
life created on the day of Jupiter;
males and females created on the day of Venus;
and "rest" created on the day of Saturn.
The oldest testimony for the existence of day dedications in the Zoroastrian tradition is attested in Yasna 16 where their God is mentioned first and after every 6 deities after that making 30 dedications in all which is approximately the number of days in a lunar cycle.
Is there any reason that the idea of the world having been created in 7 days in Genesis, God having rested on the 7th, wouldn't have originated among the Zoroastrians?
Because, as you show, Iran still kept to the "quarter-phase" week, in which not every cycle was seven days, but one or two extra are inserted to make 29 or 30. The only place I know where the quarter-phase week is still functioning is Thailand, where the
phan wat "auspicious day" for visiting a Buddhist temple is the quarter-phase day, sticking to the same "weekday" (in the sense of the strict-seven-day week) two or three times in a row before slipping to the next; the custom at some time must have been universal in south Asia.
Your argument as usual amounts to:
1. This custom is very ancient and found in multiple cultures
2. Iran is one of the cultures where some form of it is found
3. Therefore, Iran must have had it first, and everybody else's version of it must have derived from Iran.
It appears, rather, that although "Magian" later came to be used often as a synonym for Chaldean-style astrologer,
in the time and place of Zoroaster (rather far from Mesopotamia) the Chaldean-style strict-seven-day week had not been heard of yet.
