One of several stories tells of long ago, young Richard Joyce set sail in his fishing boat from a village near Galway City. A band of Moorish pirates boarded his boat, and on finding only a few fish, decided to abduct Joyce and forced him to join their crew. He ended up as a slave in Algiers where he worked melting down gold plundered by the pirates. Later, his task was to fashion the gold into new medallions and other jewellery, and he developed a skill as a goldsmith.
Eventually, in 1689, he was released and made his way back to Ireland, where he married. Favouring his new skill as a goldsmith over the perils of the sea, Joyce and his wife started business making jewellery, and his specialty was a ring that included a love heart.
And the name of the fishing village? Claddagh.
If a girl wears a Claddagh ring on the right hand with the crown turned inwards, it means she is waiting for her lover to make himself known. When he does this, and while she's considering her own feelings toward him, she turns the ring so that the heart faces outwards. When she is ready for the relationship to advance further, she wears the ring on her left hand. In Ireland, engagement or wedding rings sometimes have the Claddagh design.
When combined with a cross, the Claddagh ring has the additional meaning that the couples' love is based on their Christian faith.
Royals tend to have an extensive collection of jewellery, but the Claddagh ring in particular was worn by Queen Victoria, Queen Alexandra and King Edward VII.
See also the Crown Cross.