The sword manufactory of Toledo acquires its greatest importance during the Renaissance period until the end of the 17th century, when it terminated. It was re-established again in 1760 under the patronage of the Government, and continues to work in the present day. Don Francisco de Santiago Palomares wrote, in 1772, an "Account of the Sword Manufactory of Toledo," the manuscript of which exists at the Academia de la Historia (E. 41). The most interesting part of this study consists in the details given upon the manner of tempering the blades. The names he has collected of the most remarkable artists, are taken from the original dies of their marks which existed at the Archives of the Ayuntamiento at Toledo. These marks have been published in the "Catalogo de la Armeria," Madrid, 1849, from which I copy them. It must be borne in mind that Palomares, after quoting the text by the Poet Gracio Falisco, which I have given at the beginning, does not establish any definite fact which enables us to study the historical progress of this manufactory during the Middle Ages. The author says, p. 111: "At the beginning of this industry there was no centralization or monopoly in this manufactory, some armourers formed a guild, placing each artist in his proper place. The kings of Castille granted them privileges of different kinds." Bowles says, in his "Introduction to the Natural and Geographical History of Spain," that the steel used at the manufactory of Toledo was taken from an iron mine existing at a league from Mondragon, the only one then known in Spain. The celebrity of Toledo blades has excited the curiosity of many who wished to ascertain the cause of their great excellence and renown. Some supposed the sword manufacturers of Toledo possessed a secret for tempering their arms: it was not so, however; their only secret being the waters of the Tagus and the fine white sand on its banks. This sand was used for cooling the steel: when the steel was red-hot, and began to give forth sparks, it was uncovered a little and sprinkled with sand, and sent on to the forgers. As soon as the blade was ready it was tempered in the following manner: a line of fire was made and the blade placed in it in such a manner that only four-fifths of its length should touch the fire. As soon as the blade was red-hot it was dropped perpendicularly into a bucket of Tagus water; when cold, if it was found to be bent, a small portion of sand was poured on the yoke, the blade was placed upon it, and beaten until properly straightened. After this the fifth part of the blade was fired, and when red-hot was seized with tongs and rubbed with suet, which soon began to melt; after this the blade was sent to the grinding-stones, and finished by being polished by wooden wheels with emery powder.