Giovanni Ambrogio Mazenta

Giovanni Magenta (; 156523 December 1635) was an Italian Catholic priest and architect. He designed the cathedral of San Pietro at Bologna, later modified by Alfonso Torreggiani (1765). He designed the church of Santissimo Salvatore in Bologna (1605–1623) and San Paolo (begun 1606).

Life and works Giovanni Magenta came from a distinguished Milanese family, and was educated as a humanist scholar; he entered the Barnabite Order in 1591, becoming General in 1612, a post he held for five years. The Order’s extensive building programme took Magenta to various parts of Italy, but his most important works were in Bologna in the first quarter of the 17th century; his role in later projects, however, seems to have been only advisory. Magenta designed three churches in Bologna: Santissimo Salvatore, San Pietro and San Paolo.

Santissimo Salvatore was completed to Magenta’s design of 1605 by Tommaso Martelli in 1623. The plan appears to be based on that of the Church of the Gesù (1568), Rome, by Jacopo Vignola, although Magenta cited the Baths of Diocletian, restored by Michelangelo in 1561 as Santa Maria degli Angeli e dei Martiri, as the source of the free-standing interior columns. The nave bays, with their side chapels, are of unequal length; the longer, central bay is groin-vaulted. This, together with the tall arches to the side chapels, creates a transeptal effect in the nave, so that the impression conveyed is of a compact Greek-cross unit, with the crossing and sanctuary, both without columns, as an addition; early drawings show this clearly. The interior remains monochromatic as originally designed, spared the addition of decoration common to early Baroque churches. The façade was also based on the Church of the Gesù, but the unadorned brick wall surface, with the entrance portal unconstrained within the architectonic frame, shows north Italian tendencies. Santissimo Salvatore was influential for later Baroque churches.

Magenta’s other two Bolognese churches were less robustly articulated. In his design of 1605 for the rebuilding of the cathedral of San Pietro, Magenta retained the choir (1575) by Domenico Tibaldi, and he added a separate nave with alternating high and low nave-arcade arches. He later added bays to each end to integrate it with the choir. Work was started in 1608 by Floriano Ambrosini and was continued by Nicolò Donati, who altered Magenta’s design, from 1612. The church of San Paolo (1606; altered 1634) conformed more faithfully to the Gesù type but with distinctive lateral illumination in the vault.

From 1612 to 1620 Mazenta lived in Milan; he made designs for the churches of San Carlo ai Catinari, Rome, with a Greek-cross nave supported by free-standing columns, later executed by Rosato Rosati with piers; and for San Giovanni delle Vigne (1618; altered 1736), in Lodi, Lombardy, also with a row of free-standing columns. While serving the Order in Rome between 1620 and 1626, he designed San Paolo, Macerata (executed 1623–1655 by Antonio Ursuzio), which was a modest version of Santissimo Salvatore. From 1626 Magenta travelled extensively as a Visitor; he made designs for the churches of San Giovanni in Acqui Terme, Piedmont; San Carlo , Arpino, Latium, with an octagonal plan similar to Borromini’s San Carlo alle Quattro Fontane (1638–41), Rome; and, his last work, San Carlo alle Mortelle (1635) in Naples.

Leonardo's journals Leonardo da Vinci's notebooks were entrusted to his pupil and heir Francesco Melzi after Leonardo's death for publication. After Melzi's death in 1570, the collection passed to his son, the lawyer Orazio, who initially took little interest in the journals.