One old historian who has studied Islam put it to me this way. He said that not enough people were converting to Islam which angered Mohammed so he wrote the Quran to make its followers force people into submitting to it. It worked.
Mohammed started in Mecca. In 13 years he made about 150 converts. He was eventually run out of town and fled to Medina. He changed his tactics to bloody jihad and conquered all of Arabia and beyond. Had he stuck to his earlier peaceful proselytizing we would never have heard of him or Islam.
That’s historically correct. When Mohammad was at Medina, he was promulgating the First Given Half of the koran (only he didn’t know it would become only half at the time). He had a whopping 150 followers who bought into his plagiarism of parts of the Bible and the Torah.
How Mohammad came to the Second Given Half is speculation. However, once proclaimed, according to Mohammad himself, the First Given Half was null, void; there would only be the Second Given Half.
Present day confusion arises from the mishmash of scrolls, oral traditions, and tapestries from which the koran was compiled 200 years later - First and Second Half suras were combined as one whole.
Now the only way to tell the difference is to read the Hadiths and Sunnahs which chronicle the life and sayings of Mo in Islam’s four other ‘holy’ books, these are Talibari, Muslim, Isaq and Bukhari; Hadiths are Mohammed’s word to his followers, The Sunnahs are the history of Muhammad and; his motto (sic) was “Kill, kill, kill” ... not turn the other cheek ...