The architectural design is that frequently used in hospitals of the Late Middle Ages, arranging the rooms around a central courtyard as was seen in several secular buildings in Florence.[5] Details are presented in the capitals of the columns and moldings that imitate Roman forms, however there is a great debate between the sources of inspiration for the building, some relate it to Roman architecture while others claim that it hardly has elements from the classical world with Corinthian capitals or also posing a resemblance to the Byzantine world; More specifically, the gallery of vaults with domes of the portico of the Hospital of the Innocents can be compared with a similar solution used in the narthex of the Basilica of San Marco in Venice[7].** However, even if the design of the capitals was not clear, this would not prevent the society of the time from wanting to replicate the great courtyards with classical designs throughout European history.[6] Brunelleschi connects the ancient Romans with the new ones. Florentines, but without copying any but may even misinterpret them, an example would be the Baptistery, which did not seem to make a direct reference to a Roman temple.[6]​.

Regarding the constitution of the façade, it consists of an open loggia with nine semicircular arches that appear connected by columns of compound order. As for the spandrels, these are decorated with circular sculptural reliefs.[4]​ The architectural elements were articulated in gray stone, the pietra serena (due to its gray-blue color) that stands out against the white of the walls. Likewise, the novelty of using proportional logic would be integrated, including the height of the columns, drawing a horizontal line along the height and creating a square between height and intercolumn distance.

The columns found in the Hospital of the Innocents are intended to fill the space left by the arches with a ceramic tondo; they are medallions made of polychrome terracotta that will be characteristics of the Florentine style in architecture. At first, few colors are used; white, blue, green and some yellow. Originally, Brunelleschi thought they were empty concavities, but between 1463 and 1466 Andrea della Robbia was commissioned to fill them with sculptural details.[5]​.

These medallions represent baby cherubs in an attitude of supplication, who symbolically wear the clothes made by those who were in charge of looking after abandoned children at that time, the silk merchants of Florence. Probably the 10 central medallions, mounted in 1487, are the work of Andrea della Robbia while the remaining 4, two pairs at the ends of the loggia, were installed in 1845 during later extensions[5].

On the other hand, at the far right of the porch there was a kind of basin next to a large window that led to a room, where a lady took turns waiting for the arrival of some abandoned child, whose first cry warned of her presence; This system lasted until 1660, the year in which the famous "wheel" or "lathe" in which the children were placed was built, now located at the left end of the portico which will remain until 1875. Likewise, the inscription at the top of this portico corresponds to Psalm No. 26 of the Bible in Latin "Pater et mater reliquerunt nos, Dominus autem assumpsit" (Our fathers and mothers have abandoned us, the Lord on the contrary has welcomed us). By turning this wheel, the child entered an inn in which the image of Joseph and Mary left the exact space in which this mechanism fit, meaning that, at least for a few moments, the abandoned minor will occupy the place of Jesus-child.[5]​.

Many artists, then famous, contributed to its construction and ornamentation, such as Luca and Andrea della Robbia, il Rossellino (1427-1478/1481), Filippo Lippi (1406-1469), Giuliano da Sangallo (1445-1516), Piero di Cosimo (1462-1521) and Domenico Ghirlandaio (1449-1494)[5]​.

Possibly the most notable works within the gallery are the following:

Deepening his knowledge of the quadrivio disciplines and systematically taking advantage of it in his professional work, he created in himself that new mixture of the liberal and mechanical arts that marked the path of applied sciences today.[8]​.

Brunelleschi carried out a new work on perspective, proposing a sense of proportions, the visual harmony of the organization of masses and space using the use of technical devices that helped him achieve the final work. This practical science is based on the understanding of classical and medieval traditions, to the extent that he had access to them once he understood the characteristics of both, with the study of both he made a synthesis that is reflected in the Hospital.[8]​.

On the other hand, Leon Battista Alberti would reduce this perspective into a theory that was previously promoted by Brunelleschi as a method of geometric construction that allows an exact interpretation of a system of objects as it is represented in view and determine proportional relationships of the different objects perceived through the mathematical laws contained in this perspective although they were already kept in mind for painting, what Brunelleschi wants and achieves in his architecture.[8]​.

The work would be carried out between 1421 and 1424. You can see what has been defined as a signature of its style, the linear motif of the arch or better, the archivolt turned on columns. That is why, in order to support a wall through a loggia, Brunelleschi aspires above all to give the arches maximum light, achieving this by reducing the supporting elements to a minimum. Among them, the arch, with its tense curve, is the link between two opposite geometric entities: the surface and the perspective depth; The span of the arch is equal to the height of its supports and the hood is worked in the shape of a cube. The cube is the ideal image of the perspective space, which is why the empty space contained in each chamber is theoretically the entire space, that is, it is all the geometric depth that can be represented.[9]​ The new chambers of the portico, each of which is covered by a hollow vault, constitute a series of cubic spaces that allow the elemental space to be reduced by playing as much as possible with perspective. Therefore, in the Portico of the Innocents, Brunelleschi demonstrates the reduction of depth in the plane, not interpreting the viewer in front of the space but as the idea of ​​a look from the ground towards the scene of a theater.[10]​.

On the other hand, a relationship is presented with the Basilica of San Lorenzo (1423) since it symmetrically develops the theme raised in the porch of the Hospital of the Innocents, the same superposition of a flat surface on a succession of arches on both sides of the nave is presented. Also for the series of bells that make up the side naves covered with hollow vaults, that is, the entire set of the portico, its front and its depth of square-based modules as made up of each of the side naves of San Lorenzo.[9]​.

Finally, Brunelleschi's porticos are places of conversation and solace for people who no longer fight for policies, but for parties. Sometimes the discussion is more about the quality of works of art, it is a chivalric, fanciful taste typical of the quattrocento that has infected commoners.[11]​.

The architectural design is that frequently used in hospitals of the Late Middle Ages, arranging the rooms around a central courtyard as was seen in several secular buildings in Florence.[5] Details are presented in the capitals of the columns and moldings that imitate Roman forms, however there is a great debate between the sources of inspiration for the building, some relate it to Roman architecture while others claim that it hardly has elements from the classical world with Corinthian capitals or also posing a resemblance to the Byzantine world; More specifically, the gallery of vaults with domes of the portico of the Hospital of the Innocents can be compared with a similar solution used in the narthex of the Basilica of San Marco in Venice[7].** However, even if the design of the capitals was not clear, this would not prevent the society of the time from wanting to replicate the great courtyards with classical designs throughout European history.[6] Brunelleschi connects the ancient Romans with the new ones. Florentines, but without copying any but may even misinterpret them, an example would be the Baptistery, which did not seem to make a direct reference to a Roman temple.[6]​.

Regarding the constitution of the façade, it consists of an open loggia with nine semicircular arches that appear connected by columns of compound order. As for the spandrels, these are decorated with circular sculptural reliefs.[4]​ The architectural elements were articulated in gray stone, the pietra serena (due to its gray-blue color) that stands out against the white of the walls. Likewise, the novelty of using proportional logic would be integrated, including the height of the columns, drawing a horizontal line along the height and creating a square between height and intercolumn distance.

The columns found in the Hospital of the Innocents are intended to fill the space left by the arches with a ceramic tondo; they are medallions made of polychrome terracotta that will be characteristics of the Florentine style in architecture. At first, few colors are used; white, blue, green and some yellow. Originally, Brunelleschi thought they were empty concavities, but between 1463 and 1466 Andrea della Robbia was commissioned to fill them with sculptural details.[5]​.

These medallions represent baby cherubs in an attitude of supplication, who symbolically wear the clothes made by those who were in charge of looking after abandoned children at that time, the silk merchants of Florence. Probably the 10 central medallions, mounted in 1487, are the work of Andrea della Robbia while the remaining 4, two pairs at the ends of the loggia, were installed in 1845 during later extensions[5].

On the other hand, at the far right of the porch there was a kind of basin next to a large window that led to a room, where a lady took turns waiting for the arrival of some abandoned child, whose first cry warned of her presence; This system lasted until 1660, the year in which the famous "wheel" or "lathe" in which the children were placed was built, now located at the left end of the portico which will remain until 1875. Likewise, the inscription at the top of this portico corresponds to Psalm No. 26 of the Bible in Latin "Pater et mater reliquerunt nos, Dominus autem assumpsit" (Our fathers and mothers have abandoned us, the Lord on the contrary has welcomed us). By turning this wheel, the child entered an inn in which the image of Joseph and Mary left the exact space in which this mechanism fit, meaning that, at least for a few moments, the abandoned minor will occupy the place of Jesus-child.[5]​.

Many artists, then famous, contributed to its construction and ornamentation, such as Luca and Andrea della Robbia, il Rossellino (1427-1478/1481), Filippo Lippi (1406-1469), Giuliano da Sangallo (1445-1516), Piero di Cosimo (1462-1521) and Domenico Ghirlandaio (1449-1494)[5]​.

Possibly the most notable works within the gallery are the following:

Deepening his knowledge of the quadrivio disciplines and systematically taking advantage of it in his professional work, he created in himself that new mixture of the liberal and mechanical arts that marked the path of applied sciences today.[8]​.

Brunelleschi carried out a new work on perspective, proposing a sense of proportions, the visual harmony of the organization of masses and space using the use of technical devices that helped him achieve the final work. This practical science is based on the understanding of classical and medieval traditions, to the extent that he had access to them once he understood the characteristics of both, with the study of both he made a synthesis that is reflected in the Hospital.[8]​.

On the other hand, Leon Battista Alberti would reduce this perspective into a theory that was previously promoted by Brunelleschi as a method of geometric construction that allows an exact interpretation of a system of objects as it is represented in view and determine proportional relationships of the different objects perceived through the mathematical laws contained in this perspective although they were already kept in mind for painting, what Brunelleschi wants and achieves in his architecture.[8]​.

The work would be carried out between 1421 and 1424. You can see what has been defined as a signature of its style, the linear motif of the arch or better, the archivolt turned on columns. That is why, in order to support a wall through a loggia, Brunelleschi aspires above all to give the arches maximum light, achieving this by reducing the supporting elements to a minimum. Among them, the arch, with its tense curve, is the link between two opposite geometric entities: the surface and the perspective depth; The span of the arch is equal to the height of its supports and the hood is worked in the shape of a cube. The cube is the ideal image of the perspective space, which is why the empty space contained in each chamber is theoretically the entire space, that is, it is all the geometric depth that can be represented.[9]​ The new chambers of the portico, each of which is covered by a hollow vault, constitute a series of cubic spaces that allow the elemental space to be reduced by playing as much as possible with perspective. Therefore, in the Portico of the Innocents, Brunelleschi demonstrates the reduction of depth in the plane, not interpreting the viewer in front of the space but as the idea of ​​a look from the ground towards the scene of a theater.[10]​.

On the other hand, a relationship is presented with the Basilica of San Lorenzo (1423) since it symmetrically develops the theme raised in the porch of the Hospital of the Innocents, the same superposition of a flat surface on a succession of arches on both sides of the nave is presented. Also for the series of bells that make up the side naves covered with hollow vaults, that is, the entire set of the portico, its front and its depth of square-based modules as made up of each of the side naves of San Lorenzo.[9]​.

Finally, Brunelleschi's porticos are places of conversation and solace for people who no longer fight for policies, but for parties. Sometimes the discussion is more about the quality of works of art, it is a chivalric, fanciful taste typical of the quattrocento that has infected commoners.[11]​.