Complex sentence: The museum has a collection of items which relate to Jewish customs from Europe, Asia and Africa, dating back as far as the 18th Century and mostly from the region to the east of river Rhine and countries around the Mediterranean.
Split into simpler sentences: The museum has a collection of items which relate to Jewish customs from Europe, Asia and Africa dating back as far as the 18th Century. These are mostly objects which came from the region to the east of river Rhine and countries around the Mediterranean.