Please read this article by Dr. Rafat Amari: RAMADAN AND ITS ROOTS
It has mentioned some interesting things, for example it says:
The Sabians, who were pagans in the Middle East, were identified with two groups, the Mandaeans and the Harranians. The Mandaeans lived in Iraq during the 2nd century A.D. As they continue to do today, they worshipped multiple gods, or “light personalities.” Their gods were classified under four categories: “first life,” “second life,” “third life” and “fourth life.” Old gods belong to the “first life” category. They summoned deities who, in turn, created “second life” deities, and so forth. |
And
Mythological roots concerning Harran’s celebration of the moon explained the disappearance of the moon after it joined with the star cluster, Pleiades, in the constellation of Taurus. It occurred during the third week of March. The people prayed to the moon, pleading for its return to the city of Harran, but the moon refused to return. This is thought to be the explanation for why they fasted during this month. The moon did not promise to return to Harran, but it did promise to return to Deyr Kadi, a sanctuary near one of the gates of Harran. So after this month, the worshippers of Sin, the moon, went to Deyr Kadi to celebrate and to welcome the return of the moon.[viii][8] According to Ibn al-Nadim, the historian mentioned earlier, the Harranians called the feast al-Feter عيد الفطر , the same name by which the feast of Ramadan is named[ix][9].
|
I think the name of "Ramadhan" can have the same origin, the second part of the word (Dhan) could be the same "Sin/Saen" or Sumerian "DNanna" like in Naramsuen (Beloved of Sin), and the first part is "Rama", you can see this name in the Mandaean texts, as you read here: The Origin of Mandaean: "Ram, which means peace and eternal rest in Avesta, is changed as Rama rabba Kabira, the powerful angel of the higher world, in Mandai texts."