Laurentian Library

San Lorenzo, Florence, 1523-59

Architect:  Michelangelo







Although Cardinal Giulio de' Medici first conceived of building a library at the monastic complex of San Lorenzo in Florence, the family church of the Medici family, in 1519, he did not commission it until late 1523 or early 1524, just after his accession as Pope Clement VII.  For its design, he called upon Michelangelo, who was already working for him there on the Medici Chapel.



The library was built to house the Medici family's famous collection of books and manuscripts, which had been greatly expanded by Lorenzo the Magnificent.  The Pope transferred this collection from the Palazzo Medici to the monastery connected to San Lorenzo.


Rooms Built

The library was to have had three rooms, but the one for rare books was not built.


Reading Room. The reading room is a long room furnished with slant-top desks to which the books were chained.  


Vestibule. Because the reading room is upstairs, a vestibule, also called a ricetto, was built next to it.  This chamber contained a scalone.  


Rare Book Room

The plan of a room intended for rare books, which was never built, dates back to the mid-1520s.  The room was to be located to the south of the reading room.


The plan's triangular shape reflects that of the space available.  Instead of hiding its irregular shape, Michelangelo emphasized it by arranging the desks parallel to the outer walls in a maze-like configuration.


This room was to be lighted from skylights because it would have been enclosed by other rooms on all sides.





Early Instance of Mannerism

The vestibule is significant in architectural history as an early and brilliant example of Mannerism.


The room's Mannerist qualities, which are expressed by structural features like the staircase and the recessed columns, are more thorough-going than those of the Medici Chapel, whose manifestations of this style were primarily ornamental.


Early Example of Italian Library Design

In having a central corridor between rows of desks beside windows, the reading room follows the arrangement of Michelozzo's library of San Marco.  In not being divided by supports, Michelangelo's design took a step toward the open room with shelves that appeared later in the century at El Escorial, a royal palace in Spain.


See more about the design of Renaissance Librarie



Early Accentuation of Staircase

The vestibule is the first site where an interior staircase was made the center of attention.  In making the staircase a major architectural feature, Michelangelo began a trend toward using monumental staircases, a form that was to become a hallmark of Baroque architecture.





1523/24:  Commission to Michelangelo.  Pope Clement VII commissioned Michelangelo to build a library at the monastery of San Lorenzo.


1524:  Beginning of construction. Construction was begun in 1524.


1526:  Slowing of construction. The Pope directed that Michelangelo's other project at San Lorenzo, the Medici Chapel, be given priority.


1527:  Medici Expulsion from Florence. After the Sack of Rome left Pope Clement without the power needed to enforce Medici rule in Florence, the Medici family were expelled from the city and construction on projects at San Lorenzo ceased.


1530:  Resumption of work. After the intervention by imperial troops that returned the Medici to power in Florence, work was resumed, but little was done until 1533-34.


1534:  Departure of Michelangelo. Michelangelo moved from Florence to Rome, and work ceased.


1549-53:  Installation of floor and ceiling.  The floor and ceiling of the reading room were installed.


1558-9:  Building of staircase. In 1558 Michelangelo sent a clay model for Ammannati to follow in building the staircase, which was completed the following year.


1571:  Opening of Library. Although the articulation of the upper story of the vestibule had only been completed on one wall, the library was opened in 1571.





Location above an Existing Structure

The library was built as a third-story addition over the west wing of the cloister of San Lorenzo.  Other than reinforcing its structure with arches and piers, the Pope would not allow any alteration to the existing architecture.


Conditions Posed by the Site

The library's location and the fact that the cloister had not been designed to carry an additional story had several ramifications for its design.


Predetermination of dimensions. It was necessary to place the new walls directly over those of the story below to avoid the necessity of adding new piers to the lower story. 


Minimization of wall weight. Because the walls of the old structure had required reinforcement, it was necessary to minimize the weight of the new upper walls.  Instead of building heavy masonry vaults, Michelangelo used a post-and-lintel system of framing to carry the roof, which made it possible to fill the spaces between the supports with lighter, non-weight-bearing construction. 


Limitations on window placement. Because the vestibule area was surrounded by existing parts of San Lorenzo, illumination was a problem.  Michelangelo proposed that windows be placed in the ceiling, but Pope Clement rejected this solution because of the difficulty that cleaning them would have posed.  To provide windows in the walls required that a third story be added to make the vestibule taller than the surrounding structures.  At 44-feet high, the room's height is greater than its width (34 feet) or depth (31 feet). 








The emphasis was placed on the second of the vestibule's three stories, which is well above eye level for observers standing on the floor or the lower stairs.



There are no features on the ground level that enable the observer to gauge a sense of human scale.





Pairing of Columns

The columns are used in pairs.  Two pairs of columns lie on each wall, and single columns stand in the corners, where they form pairs with the corner columns of the adjacent walls.  The same arrangement is repeated on the top story using pilasters instead of columns.


Placement of Columns in Niches

Freestanding pietra serena columns stand in the recesses within the walls.  (Michelangelo also used recessed supports on a smaller scale in the frieze of the Medici Chapel, which he was working on during the same period.)


Because of the necessity of concentrating the weight of this story over the walls below, placing the columns in the walls was the only way that freestanding columns could be used.


Pilasters line the sides of the niches.


Inversion of Projecting Columns

By placing the load-bearing columns within sections of decorative walls, Michelangelo inverted the traditional practice of using decorative columns in front of load-bearing walls.


The entablature is also reversed, and the ressauts correspond to wall sections instead of columns.


Use of Consoles

Attention is called to the recessed columns by the huge consoles below them.  The presence of the scrolls suggests that the columns need to be supported, but their curving shape and the fact that they are not as deeply recessed as the columns casts doubt on their capacity to do so.


The consoles are only recessed slightly because the space directly under the columns is occupied by piers that support them within the walls.





Blank Central Area

The series of tabernacles, which are located between the pairs of columns, are empty. Because a tabernacle generally functions to shelter and emphasize something within, leaving such an emphatic feature empty is an inversion of its function.


Because the tabernacles are comprised of pietra serena, they stand out more strongly than those of the Medici Chapel, which are constructed of lighter-colored materials.



The pilasters forming the tabernacles' side members are unique in two respects.


1.Downward taper. The pilasters are tapered downward, in contradiction to all known precedents, except for ancient Minoan columns, which were unknown in the Renaissance.  This feature has the optically corrective effect of making the edges of the pilasters appear parallel despite the recession resulting from viewing them from below.


2.Horizontal divisions. The pilasters are divided into three distinct zones by different surface treatments that progress upward from shallow narrow flutes at the bottom, to deep wide flutes in the middle, and finally to the absence of flutes at the top.





Blind Panels over Tabernacles

The spaces between the entablature and the tabernacles contain panels that are set within larger panels in an arrangement that reduces the weight of the walls.


Ornament is concentrated at the tops of both the inner and outer panels.


The arcs of the garlands and the U-shapes of the top edges are mirrored by the arcs of the segmental pediments below and the inverted U-shapes of the bottom edges of both the tabernacles below and the windows above.


Crowding of Features

The various features are crowded together so that their edges nearly touch.


The pediment over the door to the reading room is significantly wider than the space between the niches flanking the door, and consequently it overlaps the columns, pinning them in their niches.


Sculptural Wall Treatment

The wall surface is vigorously sculpted by several means.


Projections. The trims of the tabernacles and the doors project outward from the wall in high relief. 


Recessions. Niches within the tabernacles and behind the columns and pilasters hollow out much of the wall. 


Discontinuities. Linear features like the entablature and the trim of the pediment over the door are interrupted in plane. 





Types of Staircase Considered

Michelangelo's drawings for the staircase indicate that he also considered splitting the aisle into left and right sides, which would have left the center of the room open.  This type of staircase would have been too wide to have been appreciated as a complete entity in a space the size of the vestibule.


Original Design

The pope gave Michelangelo permission to abandon the wall flights, and thus began his more creative sculptural project, a staircase that would fill the room, creating a focal point of great beauty.


When Michelangelo left Florence in 1534, the stairs had been designed but not begun.


1558 Model

In 1555 Vasari, who was currently working with Ammannati on completing the vestibule in accordance with the original plans, wrote to Michelangelo in Rome asking what he had intended for the staircase.


Michelangelo replied that he had forgotten, and three years later he sent a clay model of a staircase.  The model and his written descriptions became the basis of its construction in 1558 and 1559 by Ammannati, who had to work out many of the details for himself.


Construction Materials

Although Michelangelo had suggested that the staircase be built of fine-quality wood, it was built of stone.  The use of pietra serena unifies it with the walls, whereas the wood's more emphatic brownish tones would have created contrast with the surrounding walls and linked it to the terracotta of the floor and the wood of the doors and ceiling.


Placement of Balustrades

The balustrades of the lower flight follow the same courses as those of the upper one, even though the lower flight is substantially wider.  Consequently, the balustrade divides the wide sections into three aisles, and the outer aisles, which Michelangelo suggested were for the servants during ceremonious events, lacked safety rails.


This unusual arrangement reveals Michelangelo's creativity and desire to explore and break the boundaries of classical architecture.  His sculptural style and unprecedented use of architectural elements makes the vestibule of the library one of the more notable examples of Mannerist architecture.


Tread Shape and Flow

The shapes of the treads are treated differently in the central and outer aisles, the central ones being convex and those of the outer aisles being straight with side wings.


Center aisle. The convex treads of the center aisle suggest a downward flow that has been compared to lava.  The increased depth of the lowest three steps intensifies this effect, and the flowing curves of the scrolls at the sides of the treads further contribute to a sense of movement.  The large lateral volutes flanking the base of the upper flight also echo the suggestion of a spreading, downward flow.  


Outer aisles. On the outer aisles, the treads of every other step wrap forward on the outer edges, forming L-shaped treads whose outer sections serve as curb-like safety rails to the steps above. 



Reading Room




Differences from the Vestibule

The reading room presents a strong contrast to the vestibule in several ways.


Shape. The reading room's shape (152' x 34") is long and narrow, in contrast with that of the vestibule, which is close to square (31' x 34") and considerably taller. 


Architectural vocabulary and usage. In the reading room, single pilasters projecting from the wall plane are used in a single-story treatment whereas in the vestibule, pairs of columns and pilasters standing in recesses are used in a multi-story arrangement. 


Quiet atmosphere. The architecture of the reading room provides an atmosphere that is more conducive to intellectual concentration than that of the vestibule, where tension is generated by features like columns in tight-fitting niches.  This coordination of mood and purpose is an early instance of this approach in architectural design. 


Light-Weight Wall Construction

As in the vestibule, the wall design was planned to minimize the weight of the walls by the use of a supportive framework along with non-weight-bearing infill.


Pilasters. The pilasters, which carry much of the weight of the ceiling beams, are regularly spaced for maximum efficiency and are aligned with the buttresses below.  The use of evenly spaced pilasters was typical of fifteenth-century practice, but the paneling between them is characteristic of Michelangelo. 


Wall panels.  The large panels around the windows and the squarish panels above them are recessed and thus thinner than the rest of the wall area, which reduces the wall weight. 



The interior is evenly lit by windows in the bays of both sides and the end.  The quality of the light is softened by the use of stained glass, whose design includes the Medici arms.


In designing the window trim, Michelangelo also made studies for versions with triangular and segmental pediments.


The windows were installed in 1568, three years before the library was opened to the public.



Slant-top desks designed by Michelangelo were placed at each pilaster.


The front of each desk formed a bench that served the user of the next desk.






The ceiling, which was installed in 1549-50, was made of antique-finished timber.


Coordination with Other Features

The ceiling was coordinated with other features of the room by several means.


Warm coloring. The reddish-brown tones of the ceiling are similar to those of the terracotta floors and the wooden desks and doors.  


Floor patterns. The oval-in-rectangle design of the central repeating unit of the ceiling is repeated in the floor pattern of the central aisle, completed by Niccolo Tribolo and Santi Buglioni between 1549-53.  Both also include the ram's head motif, the symbol for Aries and the sign of Francesco de' Medici.  A different pattern that is smaller in scale is used for the areas under the desks. 


Longitudinal compartmentalization. The three-part longitudinal division of the ceiling reflects the three-part arrangement of a central aisle flanked by rows of desks. 


Lateral compartmentalization. The floor and the central zone of the ceiling have similarly spaced lateral divisions that correspond to the pilasters. 


See more about Renaissance libraries. 


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Michelangelo 3 of 6




Vestibule, Laurentian Library, 1523-59



Reading Room, Laurentian Library, Florence, 1523-59