After the invention of gunpowder and the application of cannon to the attack and defence of places, it became necessary to arrange earthen ramparts behind the thin walls of the ancient works, for the reception of the new artillery. Moreover these walls were soon found inadequate to resist the missiles of the besiegers, and it became necessary to replace them by parapets of earth. In order to cover the retaining walls of these parapets from the besieging batteries, it was also found to be necessary to lower these walls as much as possible, and to raise the counterscarps. The traces or plans of the works, however, received no material change till about the close of the fifteenth century.
It is not known who first changed the ancient towers into bastions. Some attribute it to an Italian, and with considerable show of reason, for a bastion was built at Turin as early as 1461. Achmet Pacha, it is said, fortified Otranto in this way, in 1480, but whether the system was previously known among the Turks cannot be determined. Others attribute the invention to Ziska, the celebrated leader of the Hussites. It is most probable that the transition from the tower to the bastion was a very gradual one, and that the change was perfected in several countries at about the same time.
Fortifications, like other arts and sciences, greatly flourished in Italy under the Medicis, and that country furnished Europe with its most skilful engineers. Catharine of Medicis introduced into France many of her countrymen, distinguished in this profession; among these may be named Bellamat, Bephano, Costritio, Relogio, Vorganno, the two Marini, Campi, and Hieronimo, who built several important places and directed the sieges of others. These able foreigners were rivalled by some distinguished French engineers, who laid the foundation of the "corps du Genie" which has since become a school of military instruction for the world. Among the early French engineers may be distinguished Lafontaine De Serré, Feuquières, and St. Remy. Pedro Navarro had been appointed a member of this corps, but his attention was more specially directed to mining, and we do not learn that he distinguished himself in the construction of any fortification.
In Germany, in the beginning of the sixteenth century, Albert Durer distinguished himself as a writer on fortification; his book is remarkable as containing the germs of many of the improvements which were made by those who followed him. This is the more to be wondered at as he was not a professed engineer. After him followed Spekel, a native of Strasburg, who died in 1589. His writings are valuable as showing the state of the art at that time, and the changes which he himself introduced. He was an engineer of much practical knowledge and experience, having assisted at the sieges of Malta, Golletta, Vienna, Jula, Nicosia, Famagusta, &c.
The first French engineer who wrote on fortification was Errard de Bar-le-Duc, who published near the close of the sixteenth century. As an engineer, he was rivalled by Chatillon, a man of distinguished merit. Errard fortified Amiens, built a part of the castle of Sedan, and a portion of the defences of Calais. Under the reign of Louis XIII., Desnoyers, Deville, Pagan, and Fabre were greatly distinguished. Deville published in 1628. He was a man of much learning and experience; but he is said to have adopted, both in his theory and practice, the principles of the Italian school, with most of its errors. Pagan began his military career while young, and became maréchal de champ at the age of 38, when, having the misfortune to become blind, he was compelled to relinquish his brilliant hopes. He was the ablest engineer of his age, and was also greatly distinguished in other branches of science. In his plans he inclined to the Dutch rather than the Italian school of fortification. He published in 1645.
At the close of the sixteenth century, the Dutch had been forced to resort to military defences to protect themselves against the aggressions of the Spaniards. As the Dutch were inferior in other military means, fortification became one of the vital resources of the country. Their works, however, thrown up in much haste, were in many respects defective, although well adapted to the exigencies of the time. Freytag, their principal engineer, wrote in 1630. Some of his improvements were introduced into France by Pagan. He was preceded by Marolois, (a cotemporary of Pagan,) who published in 1613.
In Germany, Rimpler, a Saxon, wrote on fortification in 1671. He was a man of great experience, having served at the sieges of Candia, Phillipsburg, Bonn, Riga, Bremen, Dansburg, Bommeln, &c. He fell at the siege of Vienna in 1683. His writings are said to contain the groundwork of Montalembert's system.
In Italy, after the time of Tartaglia, Marchi, Campi, &c., we find no great improvement in this art. Several Italians, however, distinguished themselves as engineers under the Spaniards. The fortifications of Badajos are a good example of the state of the art in Italy and Spain a that epoch. The citadel of Antwerp, built by two Italian engineers, Pacciotti and Cerbelloni, in 1568, has become celebrated for the siege it sustained in 1832.
The age of Louis XIV. effected a great revolution in the art of fortification, and carried it to such a degree of perfection, that it has since received but slight improvement. The years 1633 and 1634 are interesting dates in the history of this art, as having given birth respectively to Vauban and Coehorn. The former was chief engineer of France under Louis XIV., and the latter held a corresponding position under the Dutch republic. Coehorn's ideas upon fortification are conceived with an especial view to the marshy soil of his own country, and, although well suited to the object in view, are consequently of less general application than those of his more distinguished cotemporary and rival. The best specimens of his mode of construction that exist at the present day, are the fortresses of Manheim, Bergen-op-Zoom, Nimiguen, and Breda.
Coehorn was followed in Holland by Landsberg, an able and practical engineer, who to much reading added extensive experience, having himself served at sixteen sieges. His system was in many respects peculiar, both in trace and relief; it dispensed with the glacis, and all revertments of masonry. His plans could be applied only to marshy soils. The first edition of his work was published in 1685.