I was reading the Wiki page on Mandaeism, and it refers to the Mandaeans as being "of pre-Arab origin", but provides no explanation of what is meant by this; I've never encountered the concept of "pre-Arab" peoples before; when I've read about the region, the term Arab always seems to refer to various peoples living in the Arabian peninsula, even as far back as the reign of Cyrus the Great. Can anyone shed any light on what is meant by "pre-Arab" in this context?
The area the Mandaens arose/practiced in is in modern day Iraq, which today is 'Arab' and inhabited by Arabic speaking people. However, before the Arab/Islamic conquests c.600-700s AD the people of this area were not ethnically or linguistically Arabs. Thus the Mandaens arose in 'pre-Arab' Iraq.