Complex sentence: It was also for a long time thought to be an original Greek sculpture, and one of the finest such sculptures to have survived, but it is now recognised as a simple 1st century BC copy from a Hellenistic original.
Split into simpler sentences: It was also for a long time thought to be an original Greek sculpture, and one of the finest such sculptures to have survived. However, it is now recognised as a simple 1st century BC copy from a Hellenistic original.