This sapphire ring, which dates back almost 2,000 years, is thought to have been a beautiful piece of jewelry that once belonged to the notoriously cruel ancient Roman emperor Caligula.

A Sky-Blue 2,000-Year-Old Sapphire Ring - Fascinating Archaeological  Caligula Artifacts

This 2,000-Year-Old Sapphire Ring was Once Worn by Caligula

2,000-year-old sapphire ring that 'belonged to Roman Emperor' goes on sale  for £500,000 | Daily Mail Online