Halfcrowns minted in 1551 are the first silver coins of this denomination to circulate in England. The y mintmark is the mark of Sir John Yorke, an under-treasurer who was promoted to master of the mint during the reign of Edward VI.Halfcrowns minted in 1551 are the first silver coins of this denomination to circulate in England. The y mintmark is the mark of Sir John Yorke, an under-treasurer who was promoted to master of the mint during the reign of Edward VI.