With the adoption of a more powerful armament not only did the old pieces disappear, but a simplification of calibres ensued. France led the way in the standardizing of calibres; about the year 1550 the French king Henri II introduced his six “calibres of France.” In the English navy at this period several types were discarded, and a limit was set to the size of the largest ship gun. “The report drawn up in 1559 tells us that there were 264 brass and 48 iron guns, all of calibres down to falconets, on board the ships, and 48 brass and 8 iron in store.... The heaviest piece used on shipboard was the culverin of 4500 lbs.; throwing a 17⅓ lb. ball with an extreme range of 2500 paces; the next the demi-cannon weighing 4000 lbs. with a 30⅓ lb. ball and range of 1700 paces; then the demi-culverin of 3400 lbs., a 9⅓ lb. ball and 2500 paces; and the cannon petroe, or perier, of 3000 lbs., 24¼-lb. ball and 1600 paces. There were also sakers, minions, and falconets, but culverins and demi-culverins were the most useful and became the favourite ship guns. A contemporary wrote, ‘the founders never cast them so exactly but that they differ two or three cwt. in a piece,’ and in a paper of 1564 the average weights of culverins, demi-culverins, and cannon periers are respectively 3300 lbs., 2500 lbs., and 2000 lbs.”[50] So far, cast iron had not come into general use. The large iron guns were built up like the early Flemish bombards; the demi-cannons and culverins were all of brass. At the beginning of Elizabeth’s reign there seems to have been an attempt to replace the expensive brass by the cheaper cast iron, but later there was a reversion to brass, and it was not until the following century that cast iron was generally recognized as a material for heavy ordnance, and then only for the heaviest types. Some technical considerations may help to indicate the chief factors which determined the material and the dimensions of the Elizabethan ordnance.