Complex sentence: The birthplace of Joos van Cleve is not precisely known, however it can be assumed that he came from the Lower Rhenish region of Kleve, from which his name is derived.
Split into simpler sentences: The birthplace of Joos van Cleve is not precisely known. It is therefore likely that he came from the Lower Rhenish region or city named Kleve, from which his name is derived.