Guarino Guarini was born in 1624 and died in 1683. As a youth, Guarini received his teachings in Modena where he was a member of the Theatine order. There, he learned philosophy, theology, astronomy, and mathematics. His study of mathematics led him to a career in architecture. As an architect, Guarini is well known for four buildings: S.Vicenzo in Modena, Sicily, Ste. Anne-la-Royale in Paris, France, S.Lorenzo and Santissima Sindone in Turin, Italy. He is also known for his two architectural treatises entitled Architettura Civile and Disegni d'architettura civile et ecclesiastica as well as other literary works that concentrate on his mathematical knowledge. Moreover, there is a close alliance between his treatises and his architecture.

In these works, Guarini discusses the four aforementioned structures and includes plates of drawings and plans for churches that were built and some not built. In addition, Guarini discusses Desargue's projective geometry. "...it was this new geometry that supplied the scientific basis for Guarini's daring structures, particularly of domes." (reference 4) Furthermore, he mentions the work of his contemporaries as well as periods of architectural history (Gothic) that he favors the most.

According to R. Wittkower, "...each of Guarini's buildings (like each of his books) was an architectural 'summa'..." (reference 3). Guarini is known for two architectural devices: an openwork dome and the telescopic creation of vertical space. In the church St. Anne-la-Royale (begun in 1663 and not completed until 1720) one can see these typical aspects of Guarini's edifices. He used a lattice feature to clearly define the broken shapes of the upper regions in order to reveal the space beyond. In addition, this church uses pointed arches which reveals aspects of gothic architecture. San Lorenzo (begun in 1634 by the Theatines and Guarini started working on the church in 1666) used a typical Baroque inner dome, characterized by illusion. Also, he made use of the Islamic arch which, because of its geometry, held much mathematical appeal.

Finally in 1668 Guarini began constructing Santissima Sindone from a pre-existing structure in order to house the holy shroud. The attempt to build a proper house for this relic began in 1430. So, when Guarini began, a circular plan, an established elevation, walls reaching to the second tier and a connection to the piano nobile of the Royal Palace were already in place. Throughout this chapel, Guarini made reference to the number three. This is seen in the number of pendentives, arches, and equilateral triangles. The use of three pendentives instead of four was an "unprecedented procedure" (reference 3).

It is also in this chapel, where Guarini's architectural structures culminate in his diaphanous dome. As an architect of the seventeenth century, Guarini was influenced by other architects of the same period, known to art historians as the Baroque period of art and architecture. Various features about art and architecture were explored during this time. One important feature is optical illusionism. Although this was explored by many, the typical expression of optical illusion was through paint; even in architecture, paint would be applied to the interior of a dome in some type of picture and this would create an illusion that the dome was receding up into space. Guarini, as a prominent and innovative architect as well as brilliant mathematician, explored optical illusion in a different manner. In his Santissima Sindone, Guarini created a diaphanous dome; a geometrical optical illusion in the dome through the use of the actual structure. Furthermore, while the true Baroque style (as seen in Borromini's work) is a homogenous structure where each piece is easily read, Guarini often chooses an anti-homogenous structure that recalls aspects of the Mannerist tradition. As Meek states: Guarini "...pushed architectural creativity and inventiveness beyond the familiar Baroque world of manipulation and trompe - l'oeil illusionism" (reference 3).

Guarini was an outstanding architect of his time. Not only were his writings influential, but his complicated structures surpassed anything that had been attempted before him. He was a brilliant mathematician as well as philosopher, teacher, writer and architect. Guarini's strong mathematical background is evident for he states in one of his treatises: 'Thaumaturga Mathematicorum miraculorum insigni, vereque Regali architectura coruscat' - 'The magic of wondrous mathematicians shines brightly in the marvelous and truly regal architecture' (reference 4).

Optical Illusion & Projection in Domes: A Study of Guarino Guarini's Santissima Sindone