According to a controversial theory by Rosemarie Lierke, the vase, along with the rest of Roman cameo glass, was moulded rather than cold-cut, probably using white glass powder for the white layer. Jerome Eisenberg has argued in Minerva that the vase was produced in the 16th century AD and not in antiquity, because the iconography is incoherent, but this theory has not been widely accepted. Rediscovery and provenance One story suggests that it was discovered by Fabrizio Lazzaro in what was then thought to be the sarcophagus of the Emperor Alexander Severus (died 235) and his mother, at Monte del Grano near Rome, and excavated some time around 1582. The first historical reference to the vase is in a letter of 1601 from the French scholar Nicolas Claude Fabri de Peiresc to the painter Peter Paul Rubens, where it is recorded as in the collection of Cardinal Francesco Maria Del Monte in Italy. In 1626 it passed into the Barberini family collection (which also included sculptures such as the Barberini Faun and Barberini Apollo) where it remained for some two hundred years, being one of the treasures of Maffeo Barberini, later Pope Urban VIII (1623–1644). It was at this point that the Severan connection is first recorded. The vase was known as the "Barberini Vase" in this period. 1778 to present Between 1778 and 1780, Sir William Hamilton, British ambassador in Naples, bought the vase from James Byres, a Scottish art dealer, who had acquired it after it was sold by Cornelia Barberini-Colonna, Princess of Palestrina. She had inherited the vase from the Barberini family. Hamilton brought it to England on his next leave, after the death of his first wife, Catherine. In 1784, with the assistance of his niece, Mary, he arranged a private sale of the vase to Margaret Cavendish-Harley, widow of William Bentinck, 2nd Duke of Portland, and dowager Duchess of Portland. It was sold at auction in 1786 and passed into the possession of the duchess's son, William Cavendish-Bentinck, 3rd Duke of Portland. The 3rd Duke lent the original vase to Josiah Wedgwood and then to the British Museum for safe-keeping, by which point it was known as the "Portland Vase". It was deposited there permanently by the fourth Duke in 1810, after a friend of his broke its base. It has remained in the British Museum ever since 1810, apart from 1929 to 1932, when