ORIGIN
The primitive version(the one above) was said to have been found at the bottom of a Spanish galleon that sunk on the Irish coastline centuries ago. It was found on the hand of an unlucky sailor who went down with the ship. On the inside was enscribed the Spanish saying: 'No tengo nada, porque darte'. Roughly translated this means: 'I have nothing, for it is given unto you'.
Some say that the Queen later added the crown to the traditional version.
Another version of the story of its origin is this:
A young man on Crusade was captured and sold into slavery. He wound up in the Moorish lands, learning gold smithing in Morocco. He made his way to Ireland, where he was comissioned to make this ring for a noble family(the one below).
SYMBOLISM
It is traditionally used as a symbol of love and friendship, and as a bethrol ring. As a bethrol ring, it is said to strengthen the couple's bond. It was sometimes handed down as a family heirloom, first as an engagemant ring and then as a wedding ring.
The hands which hold the heart represent friendship, the crown which rests upon the heart represents fidelity and loyalty, and the heart itself represents love.
Worn on the right hand, with the heart pointing outward, it means that one's heart is free. Worn on the right hand, heart pointing inward, it means one is considering love. Worn on the left hand, the heart pointing inward, it means one's heart is spoken for(taken).
IT'S ROLE ON BtVS
It's the ring that Angel gave Buffy on the docks for her 17th birthday, when they thought Angel had to leave Sunnydale(in order to keep the box from getting to Spike and Drusilla, who would then assemble the Judge and destroy the world). He explained to her its meaning, and was about to tell her he loved her for the first time, when they were ambushed by Spike's vampiric followers.
Later on, in season 3, that same ring was what brought Angel back from Hell(where Buffy had been forced to send him).
Because of its many important appearances between Buffy and Angel, it has become a symbol of their love amongst Buffy/Angel fans everywhere. After he gave it to her in season two(in the episode 'Surprise'), sales of the ring soon skyrocketed.
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