MILITARY ARCHITECTURE AND THE RADIAL CITY PLAN IN SIXTEENTH CENTURY

HORST DE LA CROIX

INCE its inception around the middle of the fifteenth century, the radial city plan has proved itself to be a popular and pliant tool in the hands of urban planners, whether artists or S engineers. While its origin remains conjectural, the radial plan appears to have passed through two distinct evolutionary phases during the first century of its life. The first of these lasted from the i46o,s through the first third of the sixteenth century and saw Filarete's rudi­ mentary conception rationalized and converted into practicable designs by Francesco di Giorgio. Subsequently, the plan's aesthetic potential was tentatively exploited by such artist-architects as Leonardo da Vinci,1 Fra Giocondo (Fig. i),2 and Baldassare Peruzzi (Fig. 2),3 to whom the radial scheme became the perfect vehicle for the expression of urban ideals. Except for a faint echo in the Vitruvius publications by Cesariano (Fig. 3) and Caporali (Fig. 4),* this first wave of interest in the aesthetic potentialities of the radial plan ended with Peruzzi. Succeeding generations of artist-architects were no longer attracted to the radial scheme and the most significant urban theoreticians of the later sixteenth century, like Pietro Cataneo and Vincenzo Scamozzi, found the checkerboard plan more to their liking. The idea of the radial plan was revived around the middle of the century, but this time by a different group, the military architects. They also took their departure from Francesco di Giorgio's plans and theories but as they were more concerned with practical than aesthetic considerations, their results differed

i. Most of Leonardo's urban designs are based on the rec­ difficult to associate the archaic fortifications on this drawing tangular or gridiron system. But two drawings in the Codex with Fra Giocondo, the man who is said to have fortified Atlanticus appear to be schemes for the enlargement of the city Treviso and Padua with bastions (cf. Willich in Thieme- of Milan in the radial manner (cf. Leonardo da Vinci, II Becker, Kuenstler-Lexikon, xiv, pp. 64-68). I submit, as a Codice Atlantico, facs. ed. Ulrico Hoepli, Milan, 1894-1903, guess, that the drawing may have been done by one of Fra fols. 6$Y and 73T). These two sketches seem to have escaped Giocondo's students in France. If so, it would still reflect the the attention of modern scholars, although they appear to be friar's approach to urban planning. most eloquent expressions of Renaissance urbanism. What 3. The angry penstroke across the face of the unfinished should increase interest in these designs is the fact that later plan indicates that Peruzzi was dissatisfied with his design. His plans of Milan indicate that an eventual extension of the city idea to combine radial with rectangular features was revived was actually carried out much in the manner that had been several decades later by G. Vasari il Giovane who drew a suggested by Leonardo (cf. F. R. Hiorns, Town Planning in methodically refined version of Peruzzi's miscarriage in 1598 History, London, 1956, plan on p. 95). (Uffizi, Dis. Arch. 4530). 2. The drawing comes from volume "B" of three volumes 4. Cesare Cesariano (Di Lucio Vitruvio Pollione de archi- of drawings which have been attributed to Fra Giocondo by tettura libri dece, Como, 1521, fol. 26T) presents a plan on H. von Geymueller ("Trois volumes de dessins de Fra Gio­ which he reconstructs the Vitruvian city according to the radial condo," Melanges de P 6 cole jrancaise de Rome, xi, pp. i33f.). principle. However, it seems quite possible that this interpreta­ P. Lavedan (Histoire de PUrbanisme, Paris, 1941, 11, p. 23, tion may never have occurred to him, had he not known hereafter cited as Urbanisme) accepts the attribution without earlier radial plans by members of the Bramante circle. Since comment, while A. E. Brinckmann {Stadtbaukunst, Berlin, Cesariano spent most of his life in Milan, he probably also 1920, p. 65) questions it. It appears that the drawing is a knew Filarete's Trattato. G. B. Caporali (Vetruvio in volgar composite, derived from two sources, and that it was made in lingua, Perugia, 1536, fol. 43r) repeats Cesariano's illustra­ northern Europe. The central temple could well be by Fra tion, for which he seems to have used the identical plate. To Giocondo, as it corresponds to similar drawings of his in the this he added a cleaned-up version on which Cesariano's nar­ Uffizi. The town that surrounds this temple, however, is not row and crooked streets have been widened, straightened and only shown in a different perspective but contains houses of regularized. These are the only two radial interpretations of northern type. While this would not preclude Fra Giocondo's the Vitruvian city which have come to my attention. Fra Gio­ authorship, the mediaeval fortifications on the design certainly condo (1513), Durantino (1524), Philandri (1552), and do. Drawings attributed to Fra Giocondo in ihe Uffizi (Dis. Barbaro (1556), all interpreted the Vitruvian text in the Arch. 1691 and 1693) show that he copied and experimented traditional gridiron manner. with Francesco di Giorgio's fortification types. I would seem 264 THE ART BULLETIN strikingly from those of the earlier planners. This second phase of the radial plan's evolution does not seem to have received the attention it deserves from modern scholars. The apparent reluctance of art historians to deal with the subject of military architecture appears to be due to the fact that today all military endeavors tend to be classified among the sciences rather than the arts. It should be remembered, however, that the Renaissance did not recognize so strict a separation of concepts and that, at that time, the terms "art" and "science" were prac­ tically interchangeable. The installation of a siege battery was referred to as an art, just as the building of a church or palazzo. It was a time when the greatest artists also were the first scientists and when many significant military inventions were made by men like Francesco di Giorgio, Leonardo da Vinci, and by members of the Bramante circle. Only toward the middle of the six­ teenth century did indications appear of a breakup in the field of human knowledge and a segmen­ tation of its rapidly growing bulk into a number of separate departments. In the field of architecture, this trend was expressed by the emergence of military engineering as a profession distinct from that of civilian architecture. This split was an early symptom of the rush toward specialization which, accelerating through four centuries, has become a dominant feature of our contemporary civilization. The source of this technological diversification should be of interest not only to the historian of science, but also to the art historian. While of basic significance, the problem referred to above is dealt with only superficially in this paper, which is concerned with an appraisal of the sixteenth century radial city plan from a new point of view. Due to the art historian's lack of interest in military architecture, a misevaluation of this type of plan is perpetuating itself in modern literature. Most frequently it is dismissed with casual references to its geometric artificiality and its decorative qualities.5 It is my purpose here to subject this small but interesting episode in the history of urban planning to a more de­ tailed study than it has been accorded and to bring this segment into a more adequate focus in the context of the huge historical field.

THE DEVELOPMENT OF FIREARMS AND ITS EFFECT ON FORTIFICATION6 Of basic and obvious significance for the further development of the radial city plan, and influential for all city planning during the sixteenth century, was the improvement of firearms and the growing power and efficiency of siege artillery.7 The invention of the gun probably occurred around the year 1300 and one of its earliest authenticated uses in Europe took place in 1331, when the German Barons von Kreuzberg and von Spielemberg attacked Cividale in Friulia.8 A few years later, in 1340, the Papal forces used firearms at the siege of Terni.

5. S. Lang ("The Ideal City from Plato to Howard," the Occident as early as the 8 th century. The first authentic Architectural Review, cxn, 668, August 1952) summarizes recipe appears in a mid 13 th century Latin manuscript which this point of view when she refers to practically all of the exists in several copies and which is believed to be a trans­ 16th century's radial plans as "geometrical exercises in pattern lation of an original Greek work by Marcus Graecus of the making." 8th century (cf. Jaehns, ofxit., 1, pp. i56f.). Directly or in­ 6. The basic reference work for all those interested in the directly, both Albertus Magnus (1193-1280) and Roger history of warfare and military sciences is still Max Jaehns, Bacon (1214-1294) are believed to have depended upon this Geschichte der Kriegstvissenschaften, Munich, 1889, a monu­ manuscript. But none of these early authors mentions that this mental, critically annotated bibliography of military litera­ powder was being used for "shooting," so that the invention ture from Greek to modern times. While emphasizing the of the gun must fall somewhat later, probably around 1300. German contribution (not entirely without bias), this work Several preparatory steps were necessary before a workable is the military equivalent to Schlosser's La letteratura artistica. gun could be developed: a) the purification of saltpeter to free Valuable also is H. Delbrueck, Geschichte der Kriegskunst, it from moisture-attracting substances; b) the construction of Berlin, 1920. More specifically concerned with military archi­ a sufficiently strong barrel with a touchhole; c) the invention tecture are E. Rocchi, Le fonti storichi deWarchitettura mili- of an effective method of loading which prevented the leakage tare, Rome, 1908; L. A. Maggiorotti, Architetti e architettura of explosive gases past the ill-fitting cannon balls. This last militari, Rome, 1935. For this paper, extensive use has also defect was remedied by the insertion of a close-fitting wooden been made of Carlo Promis' devoted compilation of biogra­ plug between ball and powder charge (cf. Delbrueck, of.cit., phies of Italian military architects, which appeared intermit­ IV, pp. 29ff-); tently in Miscellanea di storia italiana between the years 1862 8. The initial introduction of cannon at the battle of Crecy and 1874 (hereafter cited as M.s.i.). in 1346 is a fable, according to Delbrueck (loccit.), who be­ 7. The composition of gunpowder may have been known in lieves that cannon were first used in Italy. This country had THE RADIAL CITY PLAN IN SIXTEENTH CENTURY ITALY 265

Once introduced into warfare, firearms underwent a fairly rapid development, which at first was directed toward increasing the size of the new weapons. By 1370, huge bombards weighing several thousand pounds were manufactured in Italy, designed to breach walls by hurling tre­ mendous stone balls against them. But even the largest of these early guns were relatively ineffective and two basic improvements had to be made before they could become efficient siege weapons. The first of these was the development of a useful and practical carriage to give mobility to these iron monsters, but even more important, stone missiles had to be replaced by iron cannon balls.9 Until the end of the fifteenth century, stone balls were used predominantly by siege artillerists, but even if reinforced with crossed iron bands, these stone missiles remained relatively ineffective, as they were fragile and tended to shatter upon impact. Thus the effectiveness of the early siege guns did not surpass greatly that of older hurling mechanisms, like the catapult and ballista. The first use of iron cannon balls on a large scale occurred during the French expedition into Italy under Charles VIII in 1494. The effectiveness of French artillery on this occasion was such that it rendered existing fortification me