Without a doubt, the murderous Renaissance excesses of Rodrigo Borgia (later Pope Alexander IV) and his son Cesare Borgia are shocking. But Lucrezia Borgia (1480-1519), Rodrigo's illegitimate daughter was a victim of extremely bad press and her supposedly dastardly deeds have been portrayed in many forms including books, opera and films. She was supposed to have had a ring with which to deliver poison. In reality, there has been no evidence to suggest that the Borgias ever used such rings.

Rings do exist that have a hinged bezel which opens to reveal a small cavity within. They were probably used as miniature pomanders. The pomanders were some perfume essence to protect against bad odours and possibly infection when going amongst the great unwashed masses long ago. Other purposes of poison or locket rings include housing a small holy relic or even a memento of a loved one - like some hair. In Elizabethan times, things got rather morbid when jewellers made mourning or funeral rings (coffin shaped, skeletons and skull decorations etc) which were given to mourners to commemorate the death of a loved one.

But all those uses are not as deliciously evil a purpose for these rings compared to poison when it comes storytelling!

References

Ernle Bradford (1967) Four Centuries of European Jewelry. Spring Books.

http://www.feelthebite.com/poisonringhistory.html

Short Biography of Lucrezia Borgia : http://www.comune.fe.it/lucrezia/bio_ing.htm

A&E Biography- Pretty Poison : Lucrezia Borgia :http://www.amazon.com/Biography-Lucrezia-Borgia-Pretty-Poison/dp/0767003292

Sarah Bradford (2006) Lucrezia Borgia: Life, Love, and Death in Renaissance Italy
http://www.amazon.com/gp/product/product-description/0670033537/ref=dp_proddesc_0/104-0859246-3515145?ie=UTF8&n=283155&s=books

Picture source : http://en.wikipedia.org/wiki/Image:Lucrezia_borgia_bartolomeo_veneziano.jpg