Al zucchero, a la mula, a le candele,
aggiuntovi un fiascon di malvagia,
resta sì vinta ogni fortuna mia,
ch’i’ rendo le bilance a san Michele.
Troppa bonaccia sgonfia sì le vele,
che senza vento in mar perde la via
la debil mie barca, e par che sia
una festuca in mar rozz’e crudele.
A rispetto a la grazia e al gran dono,
al cib’, al poto e a l’andar sovente
c’a ogni mi’ bisogno è caro e buono,
Signor mie car, ben vi sare’ nïente
per merto a darvi tutto quel ch’i’ sono:
ché ‘l debito pagar non è presente.





The  Casa  Buonarroti  in  Florence  preserves  a  series  of  ground  plans  executed  by Michelangelo for several fortifications of Florence in I529.  These  drawings, done in  pen and  bistre,  are for the  most  part  unpublished  and perhaps have  not,  up to  the  present time,  attracted sufficient attention  from scholars.1l  The  authors of general works on  the artist  have  treated  only  biographical facts,  and  have  sought to  give  some  psychological explanation for the sudden flight of Michelangelo from Florence during the siege of 1529. In monographs devoted  to Michelangelo as architect, the activity  of the artist as an architect of fortifications has been completely ignored. No special study dedicated to this series of  drawings has  yet  appeared. These  folios  are, however,  of  considerable importance, both from the point  of  view  of the development  of thee architectural genius of the  artist, of which they  are a characteristic manifestation,  and from the point of view of the history of fortifications in general, in which they mark a turning point. In  the  early  part  of  1529,  disturbing  news  was  received  in  the  Republic  of  Florence concerning the plan of Pope Clement VII  to restore, with the aid of the imperial army, the Medici, who had abandoned the city in 1527.Thereupon the Popular Government decided, upon the advice of Pietro Navarro, to perfect the unfinished fortifications of the city, begun under the reign of the Medici in 1526.15 A committee of defense, the Nove della Milizia, was established. Its mission was, according to Varchi, to “rassettare le mura, racconciare le  torri, far  bastioni,  e  finalemente  fortificare  quando  e dovunque  paresse loro  che  di bisogno facesse. Michelangelo was elected a member of this committee. Shortly there- after, on April 6,  1529, the Signori Dieci della Guerra, “judging it necessary to resist the imminent dangers that were appearing daily from the frequent assaults of the barbarians, named Michelangelo  “General Governor and Procurator of the fortifications of Florence.” He  was  appointed for the  term of  one year,  at  the salary of  one gold florin a day;  up to this appointment the artist had worked gratis as a member of the Nove. This position was given to him “in consideration of (his)virtue and discipline. The Republic of Florence evinced this confidence in Michelangelo,  despite the fact  that  he had formerly been in the service of the Medici, since there was no doubt of his republican loyalty  and it was known that he was descended from an ancient Guelph family. Furthermore, in choosing him, they recognized his qualities as a specialist in  fortifications.21 The  artist accepted the new position  and went  to Ferrara  early in August,  1529, in order to study the fortifications -there, which were considered at that time to be the most perfect and the most modern.22 The  siege  of  Florence  began  October  12,  1529,  under  the  direction  of  the  Prince  of Orange.  The imperial army,  approaching from the south, surrounded in  a semicircle the hills of the left  bank of the Arno. The siege continued for eleven months,  during which time  the  population  of  the  Republic  defended  itself  courageously  until  the  betrayal  of Malatesta  Baglioni, Governor General of the city. Benedetto  Varchi  gives the  most  precise information  concerning the  construction  of fortifications  under  the supervision of Michelangelo. We  learn  from  him  that  Michelan- gelo seems  to  have  begun the  fortifications  in  the  southern  part  of  the  city  by  surrounding Monte  San  Miniato  with  a wall,  beginning  at  the  Porta  di  San  Miniato  and  returning to  it. He made two bastions (puntoni) in the garden of San Miniato  at the west side, one bastion near the  church of St.  Francis (today  called San Salvatore)  and a similar bastion  next to the  Campanile of San Miniato.  He  constructed  another bastion  by the wall  between the Porta  di  San  Miniato  and  the  Porta  di  San  Giorgio.  This  bastion  was  known  as  the Bastione  della Fonte  alla Ginevera.  A large bastion was  erected just  outside  the walls of the  city,  between  the Porta  di  San  Giorgio  and  the  Porta  San  Piero Gattolini.  A long bastion was erected within  the walls of the  city,  between the same two gates.  Above  the Pitti  garden was created  a cavaliere (high bastion).  A fortification was  raised between  S. Piero Gattolini  and Porta  San Friano near the  church of  the  Camaldoli.  A  bastion  was erected near the church of San Donato.  Another one was raised to protect the Porticciola del Prato.  A  bastion was  erected near the  church of  Santa  Caterina  between  the  Porta di Faenza  and the Porta  di San Gallo.  A fortification was  raised between  Porta  a Pinti and  Porta  alla  Croce  near  the  Palagetto  de’Guardi.  One  fortification  was  outside  the Porta alla Giustizia.  The last was erected on the Prato d’Ognissanti. The first problem is to determine the positions for which Michelangelo intended  these drawings now in the Casa Buonarroti.  For four of them there is no difficulty, since the artist himself has given us precise indications.  Two of these four were made for the Prato d’Ognis- santi,  one for the Porta  alla Giustizia,  and the fourth for the Porta  al Prato.  Since these drawings are the most  complex and most  highly developed in conception of the series, we shall discuss them  after dispensing with  the others. Projects made probablyfor the Porta di San Miniato: There are several drawings bearing no  explanatory indications  which  are  certainly  plans for fortifications  by  Michelangelo for the  gates  of Florence.  It  is impossible to determine the  exact  position for which  the projects were intended.  Varchi says that each of the city’s gates was fortified by a bastion, and there were at that  time  eleven  gates.  Contemporary views  and maps which  give  in- formation concerning the form of these gates show that they were not fortified according to the plans of Michelangelo; they are, in fact, represented with the old tower as unfortified. Without  any doubt, three of the drawings (Figs. 6, 7, and 8 ) were executed for the forti- fication of the same gate.  In  all three, the form of the gate  and the wall is identical.  In each instance the gate has two buttresses, and the wall running from the gate on each side is straight  and is pierced on the right and left sides by gun emplacements in the form of a half-niche.  In spite of the differences in detail, the fundamental idea in all three drawings remains the same.  There is an opening in the most advanced part of the bastion, protected in  each  instance  by  an  inner wall  facing  this  opening  within  the  bastion  itself;  in  the opening the  artist  places the  drawbridge.  The  lateral walls  of the  bastion  in these  three sketches  become increasingly complicated; straight walls become curved ones. These  three projects were certainly  among the early efforts of the artist to draw plans for the fortifications of the  city,  because in the simplicity  of their geometrical form they are still close to traditional types of bastions.  Varchi says Michelangelo began his fortifications in the south  of the city  at the Porta di San Miniato. The wall of ancient Florence at this gate is straight  (as are also the walls in these three drawings).  Hence  there exists the  possibility that  these drawings might  have  been made for the Porta  di San Miniato. In  direct  relation  with  the  last  of  these  three  drawings  (Fig.  8)  are two  other  folios (Figs. 9 and 10).  They  were doubtless  executed  at the same time, for they show the same division of the lateral walls of the bastion in three curved ramparts on each side.  Further- more, there is a sketch (at the left  in Fig.  9) in which  the form of the gate  with  its  two buttresses,  the  form of the  wall with  its  two  lateral  gun  emplacements in the form of  a niche,  and the position of the drawbridge in its relation to the axis of the gate,  are almost the same  as in  the  three drawings that  we  have tentatively identified with  the  Porta  di San Miniato.  The essential difference between the three folios relating to San Miniato  and the sketches of these two folios (Figs. 9 and 10) is that in the latter, the artist has omitted the  opening in  the  bastion  and  has  replaced it  by  a  pointed  rampart  (puntone).  This arrangement had already been sketched  by Michelangelo  (see Fig.  8, upper left). The sketch in the upper center of  Figure io  shows a bastion  almost identical with  the bastion in Figure 9.  In the former, however, the bastion is at the angle of the walls, from which we may  conclude that  this sketch  applies rather to the Porta di San Piero Gattolini (no.  139  on  Bonsignori’s map),  the  only  gate  in  the  south  part  of  the  city  which  has  a similar arrangement. Three projects for  undetermined gates: Three other folios (Figs.  I I,  12,  and  13)  showing rather  simple  plans  must  also  be  placed  among  Michelangelo’s  early  sketches  for  the fortifications  of the gates  of Florence.  Consequently  these must  be for the  three gates  in the south  side  of  the  city  which  have  not  been discussed up to  now,  namely  Porta  di  S. Friano, Porta  di S. Giorgio, and Porta  a S. Niccolo.  It  is impossible to say which sketch is intended for which gate. The  drawing in Figure  I I  recalls, because of its diagonal walls, what was probably the first  drawing for  San Miniato  (Fig.  6),  and seems,  further,  because  of  its  simplicity,  to have  been executed  prior to the one for San Miniato.  But  it  is not  one of the group pre- sumably  destined  for San Miniato,  because the form of the  gate  is different, and instead of one drawbridge there are two, one to the left and one to the right of the bastion, and none on the axis of the gate.  This curious disposition of the drawbridges may lead us to conclude that this sketch is a first idea of  the drawing on the right side of Figure 9 where the bridges are placed in a similar position. There  is  some  analogy  between  Figure  12  and  the  second  drawing for  San  Miniato (Fig.  7).  We find in these  two sketches  the same diagonal ramparts which  end in scrolls on  both sides of the  bastion.  However,  the plan of  the gate  and  of the walls is different from that found in the sketches for San Miniato,  and thus we must suppose that Figure 12 was intended for one of the other three gates which we have mentioned. The third drawing (Fig.  13)  was inspired by the same idea as the third probable sketch for San Miniato  (Fig.  8).  The lateral walls are divided into three curved ramparts, and the drawbridge is found on the axis of the gate.  The difference is simply that the gate lacks the buttresses, and the wall does not have the gun emplacements in the form of a half-niche. After  this final problematic sketch,  we may  now  consider the drawings for which the artist himself has given us indications. Projects for the bastion of Prato d’Ognissanti: Varchi says:  “He (Michelangelo)  finally made, ofi the Prato d’Ognissanti, near the Tower of the Serpents, a marvelous bastion, and outside, in front of the Tower, they  began to raise a quite  bold cavaliere.”30  The  position here indicated is precisely the angle of the city’s wall to the west,  on the right bank of the Arno, near the original bed of the Mugnione river (see Bonsignori, no.  21).  The  direction of  this little  river was  diverted  in I526,  and was made  to  empty into  the Arno near the Porta  alla Giustizia. Michelangelo  had  two  different conceptions for the  gate  of  Prato  d’Ognissanti.  The first version (Fig.  17) shows the Tower of the  Serpents fortified by two  orecchioni, in  the middle of which is a semicircular wall reinforced by  a pointed wall.  Michelangelo himself has  indicated  on  this  drawing the  position  of  the  Arno,  the  Mugnione,  and  the  Prato d’Ognissanti. This sketch gives us the key by which we may determine the destination  of three other folios that lack any definite inscription.  We find in Figure i6  a sketch  almost identical to that  of Figure 17.  The slight differences are explained by the fact that this drawing shows the plan for the  upper part  of  the fortification, whereas Figure  17 gives the  plan for the lowest part,  as the inscription of Michelangelo “sotto”  and “disotto”  indicates.  The note by Michelangelo  on Figure I6,  “Mugnione,” is an inscription which leaves  no doubt  that this was  a drawing for Prato d’Ognissanti. The second drawing is found in Figure i5  (upper right); it is not  catalogued by Thode. The Tower of the Serpents, the walls at right angles, and the form of the bastion (with two orecchioni) indicate  that  it  again  refers to  the  Prato  d’Ognissanti.  It  appears to  be  a preliminary sketch for Figure I7. The  third drawing of  this group  (Figure  14,  lower left)  also shows  the  Tower  of the Serpents, with  the walls at  right angles,  and seems also to  be related to the plans for the fortifications of Prato d’Ognissanti.  This latter sketch, however, appears even more hastily done than those  already discussed,  and would seem for this  reason to have  been the first drawing of this series. We  may  be  equally  certain  of  the  second  version  for Prato  d’Ognissanti  because  of inscriptions by the artist on one drawing of this group (Fig.  20). The bastion in this ver- sion is in the form of a star, but it  remains similar to that  of the first version by the dis- position of an opening between the two lateral wings.  Figure 20 gives us a possible key by which we may  determine the destination  of two  other drawings: one,  Figure  19,  bears in the  upper  left  corner  a  preliminary sketch  of  Figure  20;  the  inscription  “al  canto  del Prato”  can only  indicate  the Prato  d’Ognissanti.  The second is Figure  18,  where we find the preliminary sketches for this star-form of the bastion of Prato d’Ognissanti. Projects for  the bastion of Porta al  Prato:  Varchi says:  “Outside  the  Porticciuola  del Prato they made a very large bastion with  a very deep  moat  and some casemates. The Porta al Prato is the first gate of the west wall on the right bank of the Arno  (Bonsignori’s map,  no.  133),  just  above  the  fortifications  of  Prato  d’Ognissanti.  Michelangelo,  in  his sketch  for the  Prato  d’Ognissanti,  Figure  20,  indicated  the  position  of  this  gate.  Thereexists  a large drawing, with inscriptions by Michelangelo, for the fortification of this  gate by a bastion (Fig. 2I).33  This again is a fortification in the form of a star, similar to the sec- ond version of the fortification of Prato d’Ognissanti (Fig.  20).  It  differs from the latter in that  it lacks the round wall in the center of the bastion,  and presents a more complicated development  of the lateral wings.  This sketch further indicates  that  Figure  24  must  also be considered a plan for the Porta  al Prato, for its bastion is almost identical in form.  The reverse side of the same folio (Fig.  25)  contains  a sketch (lower left  corner) which seems to be another variant for the Porta  al Prato. Hypothetically,  we may  place Figure  23 in relation to the Porta  al Prato.  The sketch is perhaps the first drawing for this gate.  Figure 26  has  a very  complicated  bastion,  but its half-octagonal form of gate is almost identical with that of the Porta al Prato.34 Projectfor the Puntone della Porta  alla  Giustizia:  Varchi says:  “Outside of  the  Porta alla  Giustizia  there  was  a  pointed  bastion (puntone)  which  was  made  similar  in  form  to  a fortification.”35 The Porta alla Giustizia is located on the right bank of the Arno and is the first gate of the east wall of the city.  This fortification was called at the end of the sixteenth century “Baluardo di Mogibello”  (see Bonsignori’s map, no.  24).  There is only one draw- ing by the artist for this puntone.  It  bears his inscription: “la Porta alla lustitia” (Fig.  22). The pointed bastion, in this drawing, is oriented in the direction of the Arno, and dominates strategically the opposite  bank of the river. The series of sketches which we have discussed presents a development which proceeds from the simple to  the  complex in form,  and from  a geometric  conception to  an organic one.  The sketches  demonstrate  that Michelangelo  occupied himself with  all the fortifica- tions of the city,  as Varchi says,  and not simply with  the fortifications of San Miniato,  as we have  been led to believe by  Condivi and Vasari. It  seems that  none of the fortifications was executed  according to the drawings of the Casa Buonarroti.36 We  know, in fact, from the  correspondence of  Busini  that  the  Gon- faloniere Niccolo  Capponi  disagreed with  Michelangelo  about  his  plans. In  any  case, none of the  bastions designed by Michelangelo is in existence today.  Varchi says:  “Near the  church of  San Miniato  whre  was  and is  yet  rofcampanile, the  there was  a bastion.  The  walls  in  this  place  are  extant today,  but  the  bastion  seems  to  have  been  destroyed  by Duke  Cosimo  I,  who  restored  the  fortifications  of  Florence. The  earliest  bastions  were  erected  in  the  middle  of  the  fifteenth  century,  at  the  timewhen  artillery began to use gun powder and thus  reduced the  effectiveness  of the  ancient fortifications.  The new bastions were distinguished from the old towers by the fact that the walls were built in diagonal form, thus diminishing the danger of cannon fire.  Examples of this disposition  of bastions are found in the school of the Tuscan masters of fortifications before Michelangelo, such  as those  of  Antonio  da  San Gallo  in Leghorn  ( I55), those of Antonio da San Gallo the Younger for Civitavecchia (I515)  and later for the Fortezza del Basso  of  Florence (I534),  and  those  for  Perugia  (Fig.  28).  These  fortifications  were conceived  simply  as  defensive  arrangements.  They  were  always  designed in  a  purely geometric form of a polygon.  They  consisted of bastions at the corners and sometimes  in the  center  of  walls which  continued  in a straight line  between them,  and  they  were sur- rounded by moats to protect the base of the walls.  Michelangelo’s new conception consisted of this: the bastions were for him not simply defensive  ramparts, but were also considered as  centers  of  attack.  Michelangelo’s  vision  was  purely  dynamic. In  order to  lessen  the offensive  power of  the  enemy,  he  constructed  curved  and diagonal walls,  and in order to give to  these  bastions  an offensive  character he divided  the walls  into  a series of  curved ramparts, in the intervals of which he set gun emplacements. These complicated systems were practically  unapproachable, for the  enemy, in  approaching, was  in danger of  being surrounded.  The  contemporaries of  the  artist  recognized that  the  novelty  of  the  new bastions  in  Florence  consisted  in  “too  many  ramparts”  and  “too many  gun positions”; but they  unjustly  criticized these inventions  of Michelangelo. From the point of view  of military  effectiveness,  the projects of Michelangelo seem to be the most perfect fortification plans of the sixteenth  century. In fact, the possibility of a successful enemy  attack  was  reduced to  a minimum  and at  the same time  a maximum of active defense was assured.  There is no reason to be astonished that the greatest  archi- tect  of  fortifications  of the  seventeenth  century,  Vauban,  studied  with  admiration  the fortifications of Florence by Michelangelo. But  the military  conception  in these drawings is correlated with  an eminently  artistic spirit.  They  are bold  emanations  of  a sculptor’s fantasy  which  considers edifices not  as abstract geometric forms, but  as concrete living  organisms.  In fact, Michelangelo,  in one of  his  letters  (Milanesi,  p.  544),  defined  the  principle  of  architecture  as  follows:  “It is certain  that  the  members  (elements)  of  architecture  depend  upon  the  members  of  the human body.  Whoever has not been or is not a good master of the body, and especially of anatomy,  can understand nothing”  (of architecture). In the drawings of fortifications in the Casa Buonarroti, this organic principle is uppermost. However, instead of an anthropo- morphic inspiration (as pointed  out  in the  above letter),  we find a zoomorphic one.  Thebastions in the drawings remind us of cross-sections of certain crustacea. Several of these sketches in the shape of a star with their long antennae, and others in the form of orrechioni with their extended pincers, bear a relationship to cross-sections of the lobster and the crab. The forces which radiate from these bodies (gun fire) may be compared to the physiological functions of these animals. The importance  of  these  drawings in  the  architectural  development  of Michelangelo resides in the fact that,  although executed during his maturity,  which was his first period of activity in architecture, he had already developed in them ideas which were to find their full realization only in his old age.  Although their most important element is the mass of the walls, exemplified also in other architectural works of the same period (the fagade of San Lorenzo, the Medici  Chapel,  and the library of  San Lorenzo),  we find also that  the artist  considers here, for the first time, the positive  value  of the spaces between the walls. These spaces, conceived as expanding forces which penetrate and determine the form of the masses, received their greatest emphasis in the architectural drawings of his old age. Furthermore, the technique of these sketches foreshadows the technique employed in the architectural drawings of his later period.  Up to this time he had sketched his ground plans simply with pen or chalk; here we see that he employed bistre for the first time in order to accentuate the plastic mass of the walls, as he did in his later period (e.g., the ground plans of the church of San Giovanni dei Fiorentini).  In the manner of a sculptor, he models the walls as if they were of a malleable material.  Thus they  assume at times an ornamental aspect.  The  complicated star-like forms and the beautiful scrolls, which recall so much the  broken gables of the Porta  Pia,  anticipate the ideas which he was  to realize in his last  period. Michelangelo  received  commissions to  execute  projects for fortifications several times later  in  his  career.  In  1535,  he made  projects for  Civitavecchia.  In 1545-46,  1547-48,  and I56I,  he busied himself with  the fortifications  of the  Borgo in  Rome.  We do not  intend here to  treat  in detail  these later projects,  but merely wish  to point  out  the difference of conception  of  these  later  fortifications  of  Michelangelo from  that  of  his  earlier  years. We should like  to  call  attention  to  an unpublished sketch  for a fortification preserved in the Vatican  Library, probably intended for the Borgo. This sketch shows a fortification in  the  form of  a star similar to  Figure  23,  although  more  regular in  its shape than  the drawings for Florence.  Perhaps this new tendency  towards regularity in the later period of the artist may be explained by the fact that his projects for  Florence, extremely personal, were not  easily  realized;  they  were too  costly  and required too much time for execution. This  last  drawing would  appear to be an effort on  the  part of Michelangelo to  adapt  his personal idea  of fortifications  to  the  practical  requirements of  execution.

Charles de Tolnay