R. Coltman Clephan, The Tournament—Its Periods and Phases
“ Crests were usually affixed to the great helm, which was worn over the bascinet; though there are instances of their being used alone on the smaller head-piece.The heraldic crest does not appear before towards the close of the thirteenth century; a notable instance may be cited in the case of the remarkable effigy of Sir John de Botiler, in St. Bride’s Church, Glamorganshire, which dates about the year 1300. The helmet of this monument is the cervellière, which is a visor-less, saucer or shallow basin-shaped head-piece, going over the hood of mail; and the crest is embossed on its front. ”
