Some
historians like to make a
link between this occurrence of
monotheism and the development of
Judaism, theorizing that perhaps the
Jews picked up the whole idea during their
slavery in
Egypt (that they did spend time in slavery is historical
fact).
As with most ancient history, though, no smoking gun can be found to prove or disprove this theory, which leaves the details of the development of Judaism (and hence, Christianity and Islam as well) to faith or opinion.