King Louis IX of France bought what he believed to be the authentic Crown of Thorns in Constantinople in 1239, and individual thorns were distributed as gifts by subsequent French kings. John, Duke of Berry (1340–1416), brother of King Charles V of France, had this reliquary made to house a single thorn; it was probably made a few years before he commissioned his famous Très Riches Heures du Duc de Berry, and some years after he commissioned the Royal Gold Cup, also in the British Museum. Previously dated between 1401 and 1410, from evidence in John Cherry's book of 2010 the reliquary is now thought to have been made before 1397; based on the heraldic forms used, the museum now dates it to 1390–97. The Holy Thorn Reliquary was later thought to have been in the possession of Louis I, Duke of Orléans, but all recent writers prefer his brother, the Duke of Berry.
Detail of one of the Apostles (over actual size)
Its location is unknown until an inventory of 1544, when it belonged to Holy Roman Emperor Charles V, perhaps as an inheritance from his ancestors the Valois Dukes of Burgundy. It presumably passed to the Austrian branch of the Habsburgs on Charles V's death, as it is listed in several inventories of the Imperial Schatzkammer ("treasure chamber") in Vienna from 1677 onwards. It remained in Vienna until after 1860, when it appeared in an exhibition. Some time after this it was sent to be restored by Salomon Weininger, an art dealer with access to skilled craftsmen, who secretly made a number of copies. He was later convicted of other forgeries, and died in prison in 1879, but it was still not realised that he had returned one of his copies of the reliquary to the Imperial collections instead of the original. The Viennese Rothschild family bought the original reliquary by 1872, in ignorance of its provenance; it was inherited by Ferdinand de Rothschild, who moved to England, and built Waddesdon Manor in Buckinghamshire. One of the copies remained in the Ecclesiastical Treasury of the Imperial Habsburg Court in Vienna, where the deception remained undetected for several decades.
The original reliquary reached the British Museum as part of the Waddesdon Bequest in 1899, by which time its origins had been "completely lost" and it was described as "Spanish, 16th Century". Thus its history had to be reconstructed through scholarship; the meaning of the heraldic plaques on the castle base had by now been lost in both London and Vienna. The first publication to assert that the London reliquary was the one recorded in earlier Viennese inventories was an article by Joseph Destrée in 1927; the matter was not finally settled until 1959 when the Viennese version was brought to London to enable close comparison. The assembled experts from the British Museum, Victoria and Albert Museum and Kunsthistorisches Museum in Vienna agreed that the London reliquary was the original. Under the terms of the Waddesdon Bequest the reliquary cannot leave the museum; in 2011 it was omitted from the Cleveland and Baltimore legs of the exhibition Treasures of Heaven: Saints, Relics, and Devotion in Medieval Europe. Normally it is on display in Room 45, the dedicated Waddesdon Bequest Room, as specified in the terms of the bequest.