The Italian architect Giacomo della Porta (ca. 1537-1602) was the leading Roman architect in the last quarter of the 16th century.

It was formerly thought that Giacomo della Porta was a Lombard, like many of the artists active in Rome in the 16th century, and that he was related to the sculptor Guglielmo della Porta. His earliest biographer, however, stresses that Giacomo was Roman "by birth and by skill," and this is now accepted as correct, especially as his career was crowned by his appointment as "architect to the Roman people."

Della Porta may have been apprenticed to Giacomo da Vignola, whose Roman career began about 1550, but he first emerges as a follower of Michelangelo. Della Porta designed the central window of the Palazzo dei Conservatori on the Capitol (ca. 1568) after Michelangelo's death, but it is so fantastic that it surpasses even Michelangelo's daring inventions, and for this reason it was long regarded as the work of another man, since on the whole della Porta's work is quiet, restrained, and sometimes rather dull. In any case, the mannerist extravagance of the Capitoline window soon faded.

Della Porta built a new facade for Vignola's Gesù (less elegant than Vignola's original design) and the dome of St. Peter's (1588-1590). The dome was undertaken with the best engineer-architect of the age, Domenico Fontana, and they modified Michelangelo's original design considerably. It is still not known whether they increased the height of the dome by about 27 feet because they thought that had been Michelangelo's intention or because they were forced to do so by the engineering problems they encountered. Michelangelo certainly planned a dome which was a perfect hemisphere, but he also designed one in the slightly pointed shape of the executed dome. What is certain is that they created one of the most beautiful domes ever built.

During the 1580s, della Porta built a number of churches in Rome, since this was a period of active church building, when the reforms instituted by the Council of Trent were being vigorously prosecuted. He worked on at least six churches. The two most interesting are St. Atanasio and St. Luigi dei Francesi, primarily because they derive from the model, made 60 years earlier, by Michelangelo for St. Lorenzo in Florence; they have rectangular facades instead of having the center higher than the sides. Towers were also planned, but only those of St. Atanasio were built.

Della Porta was also active as a domestic architect. His most interesting civil buildings are the great loggia at the rear of the Farnese Palace (1589) and his last work, the Villa Aldobrandini at Frascati (1598-1604). The villa has an enormous broken pediment which gives it a picturesque skyline from a distance, but it is clumsy when seen close to. In 1602 della Porta was coming back from Frascati in a coach with his patron, Cardinal Aldobrandini, when he was taken ill at the gate of Rome and died on the spot.

Della Porta's work lacks the personal and inventive genius of Michelangelo's and is less correct and studied than Vignola's, yet it constitutes an aspect of late-16th-century Roman architecture which remains to this day typical of the city and of the epoch.

Further Reading

• There is no work on della Porta in English. For background material see Peter Murray, The Architecture of the Italian Renaissance (1963).