Complex sentence: The Lumley collection of paintings was largely dispersed in sales that took place in 1785 and 1807, many works from the inventories can be recognised by distinctive "cartellino" added to some (but not all) of the paintings.
Split into simpler sentences: The Lumley collection of paintings was largely dispersed in sales that took place in 1785 and 1807. Many works from the inventories can be recognised by distinctive "cartellino" added to some (but not all) of the paintings.