Cornelius Sigan's Jewel

"I've never seen a jewel like it." "That's because it's not a jewel. It's the soul of Cornelius Sigan."

- Merlin and Gaius

Cornelius Sigan's Jewel is an enchanted gemstone that contains the spirit of Cornelius Sigan. Shortly before his execution, Sigan sealed his soul inside the jewel in order to cheat death and one day return to take his revenge.

History
When Cornelius Sigan's magic grew too powerful, the King of Camelot at the time ordered his execution. Unable to bear the thought that his wealth and power would die with him, Sigan became obsessed with finding a way to cheat death. He eventually accomplished by sealing his soul inside an enchanted jewel that was entombed with his sarcophagus.

Centuries later, Sigan's tomb was unearthed by miners when Uther decided to dig beneath the citadel in search of treasure. Though Gaius advised him to reseal the tomb, Uther refused and rumours of the riches within soon attracted a thief called Cedric, who attempted to steal the jewel. When he removed the jewel from its setting, however, he released Sigan's soul from the gem and became possessed by it.

Once returned from the dead, Sigan quickly set about fulfilling his vow to raze Camelot to the ground. He was ultimately defeated by Merlin, however, who used a spell given to him by the Great Dragon to seal Sigan's soul back inside the jewel. The gem was later returned to its setting on Sigan's sarcophagus before the tomb was resealed (The Curse of Cornelius Sigan).

Trivia

 * According to Gaius, the inscription on Sigan's tomb translates to: "He who breaks my heart, completes my work" (The Curse of Cornelius Sigan).