First historical record of refined sugar

It appears from the accounts of the Chamberlain of Scotland, published from the originals in the Exchequer, that in the year 1329, loaves of sugar were sold in Scotland at the price of two shillings a pound. Stow’s Survey of London states sugar refining to have been commenced in England about 1544; and upwards of four centuries since we find Margaret Paston writing to her husband from Norwich thus: “I pray, that ye will vouchsafe to send me another sugar-loaf, for my old one is done.”