See my post at #17.
Yeah, but what HAPpened? We call Ptolemy’s astronomical work the Almagest because we got it from them, and many of the stars have Arabic names (”Alcor”,”Alkaid”, “Zubenelgenubi” and the like) . Alchemy? Of course it looks like algebra started in the Indies and only “passed through” Arabian culture. So it leads one to think that around the 13th century somebody slammed on the brakes.