History of the construction of the Basilica
The area on which the church of Sant’Andrea della Valle is now situated was defined by the so-called “di Siena” square, because the palace made to build by the Sienese cardinal Aeneas Silvio Piccolomini (then Pope Pious II) occupied it entirely. Constance Piccolomini of Aragon, duchess of Amalfi and countess of Celano left in heritance the family’s palace, on June 20th 1582, to the Regular Clerks called Theatins, the order founded in 1524 by Gaetano Thiene and John-Peter Carafa, then Pope Paul IV. The Theatins, from the ancient name of Chieti where Carafa had been bishop, took possession of the building in 1586 granting the request of the Piccolomini for erecting a church dedicated to Saint Andrew protector of Amalfi. It became patron and protector of the initiative the cardinal Alphonse Gesualdo who entrusted James Della Porta, his reliable architect, to start the project. At this point they begin the controversies for the construction of this church since the Theatins supported the proposals advanced by the architect of the congregation, Francis Grimaldi. They decided for a compromise between the two projects. Besides they acquired more space for the construction and between 1590 and 1591, the little church of Saint Sebastian was demolished to extend the road in front of the new church.
From the moment of the new setup of the area both the square end the church took name from the near residence of the cardinal Della Valle. From 1591 to 1594 they began the jobs of the construction of the foundations, while the building structure was opened in 1594 to be ended in 1596.
From 1596 to 1599 the chapels and the coverage of the vault of the nave were completed. In 1599-1600 it was commissioned the façade of the church, but after the death of the Gesualdo in 1603, they came to finish all the financial founds and the construction was suspended temporarily. In 1608 it was resumed on the initiative of the cardinal Alexander Peretti Montaldo, who gave the direction of the construction to Charles Maderno. In 1620 it was erected the octagonal drum of the dome with rectangular windows separated by coupled columns. The same architectural motif was repeated in the lantern, which was planned by Francis Borromini who personally worked to realize the original capitals. The dome, divided by ribs, was inaugurated in 1622. The church was completely covered in 1625, still thanks to Cardinal Peretti, and it was consecrated in 1650, as far as it still missed a façade worthy of that project: in fact the existing façade in this period consisted of a bare masonry without any architectural style. Eventually the architect Charles Rainaldi got the errand to complete the new façade in travertine stone, which was built between 1655 and 1665 , using the project performed by Maderno, but making it more slender and with a rich design with more marked chiaroscuro (light and shade) effects. This is the first and most important façade of the baroque architecture in Rome.