Guinevere's Engagement Ring

"Is that a 'yes'?"

- Arthur after asking Gwen to marry him the first time

Guinevere's Engagement Ring is the ring that Arthur gave her when he proposed to her the first time around.

Background
When Arthur decided that it was time for him to propose to Guinevere, he asked Merlin to help prepare for the proposal at her house. Arthur ambushed Gwen in his chambers, blindfolded her and lead her to her house where he proposed. So shocked by the question, gwen became speechless and hugged him instead of saying yes, which he replied with "Is that a yes?". Gwen proudly wore the ring during Arthur's engagement tournment as Arthur and her were officially together.

Angered that Gwen was going to become queen of Camelot, Morgana raised Gwen's old love interest, Lancelot, from the dead and made him give an enchanted bracelot to her as a wedding gift, which made all her old feelings for him return. Under the enchantment, Gwen Kissed Lancelot and betrayed Arthur; heartbroken over the betrayal, Arthur exiled Gwen from Camelot. (Lancelot du Lac).

During her exile, she wore her engagement ring around her neck as a lone memory of Arthur. After being chased and confronted by Morgana, the witch knocked the king's former fiancee unconconcious and tore the ring from her neck and threw it into the forest. The ring was later found by Arthur while on a hunt with his knights, Merlin and Princess Mithian. It was at this moment that Arthur realised that he was still in loved with Gwen despite everything that had happened between her and Lancelot. Arthur returned the ring to her after the second overthrowal of Morgana and he proposed again. Gwen is seen wearing the ring with pride as Arthur, now her husband, crowns her as the rightful Queen of Camelot (Sword and the Stone).