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The earliest reference to the Thorn is in a thirteenth-century history of Glastonbury Abbey. The tree was watched carefully every Christmas to see if the blossom appeared. After it had grown two trunks, a local superstition warned against 'cutting the Holy Thorn on Christmas Eve when you hear the buds cracking, or you will receive a curse'. Tradition states that this came from the fate of a man who had chopped down one of the trunks during the reign of Elizabeth I. When he tried to cut the second trunk, 'thorns flew into his eyes and blinded him'. The tradition of sending Christmas blooms to the Monarch began in the reign of Henry VIII. A Dr Layton was sent to Glastonbury in 1535 to investigate rumours concerning the tree. The doctor sent back to London 'two flowers wrapped in black sarsnet, that in Christmass Mass, at the very hour Christ was born, will spring and burgeon and bear blossoms'. The custom of sending blooms was stopped by Charles I, but revived in 1922 when Queen Mary agreed to receive some each time the Holy Thorn lived up to its reputation.
Queen Elizabeth II received blooms from the Thorn on several occasions but the large tree that had supplied them for eighty years was pronounced dead in June 1991, and was cut down in February 1992. It had been planted by the head gardener of Glastonbury Abbey, who had also learned how to graft Holy Thorn cuttings onto the root of Blackthorn stock, and so preserve the 'miraculous' Christmas blossoming characteristic. Attempts have been made to grow the Holy Thorn from seed and direct cuttings, but all have reverted to the normal Hawthorn type, flowering only in spring. Holy Thorns have been sent all over the world and trees survive from earlier graftings to perpetuate the Glastonbury legend. Among them are two other Holy Thorns in the grounds of St John's and in recent years the blooms sent to Queen Elizabeth II have come from these.