Complex sentence: The list presents 44 materials or sets of materials, and includes those from ancient to feudal Japan about 4500 BC to 1361, the actual number of items is more than 44 because groups of related objects have been joined to form single entries.
Split into simpler sentences: The list presents 44 materials or sets of materials from ancient to feudal Japan, spanning a period from about 4500 BC to 1361. The actual number of items is more than 44 because groups of related objects have been joined to form single entries.