The essential differences between this period and the last are: (1) the substitution of chain mail for the jazeraint, mascled, and scale armour which had formerly been used; (2) the adoption of the pot-helm or heaume as a secondary defence for the head in place of the conical helmet, the coif-de-mailles, or the pot-de-fer under the mail; (3) the introduction of the sleeveless surcoat and the crest. [Illustration: FIG. 97.--Painted “Pot Helmet,” _c._ 1241.] _The Heaume._--The term “heaume” may perhaps by some be deemed to be hardly applicable to the head-defence when first introduced, inasmuch as it was small in size, fitted closely to the head, and was in most respects a helmet. But inasmuch as a second defence was worn underneath it from its very inception, the word “heaume” is an appropriate designation, as it infers a reinforcement to an existing protection in the next few centuries during which it is constantly in evidence. It may readily be divided into two distinct classes, namely, those in which the plates composing it are riveted together so as to form one piece, and secondly, those in which a movable ventail can be affixed. Further subdivisions may be made if desired, such as flat-topped, round-topped, and sugar-loaf. The word “heaume” or helm among the northern nations simply meant a covering of any kind for the head, and we have an example in the Anglo-Saxon wærhelm, of which examples have been given in this work. Of the first heaumes the flat-topped, or those with slightly curved crowns, were probably the earliest, of which the woodcut No. 96 furnishes an example.