Ignazio Danti had become professor of mathematics…

Ignazio Danti had become professor of mathematics at the University of Bologna after leaving Florence.

While occupying this chair he has built a massive gnomon in the Bolognese church of San Petronio, the meridian line of which is still visible in the church's pavement.

He has also spent some time in Perugia, at the invitation of the governor, where he has prepared maps of the Perugian republic.

On account of his mathematical attainments, Pope Gregory XIII had invited him to Rome, appointed him pontifical mathematician and made him a member of the commission for the reform of the calendar.

He had also placed him in charge of the painters whom the Pope had summoned to the Vatican to continue the decoration of the palace, most notably to make a number of maps of the regions of modern Italy in the newly constructed Gallery of Maps along the Cortile del Belvedere.

This remarkable project, begun in early 1580 and completed about eighteen months later, has mapped the entirety of the Italian peninsula in forty large-scale frescoes, each depicting a region as well as a perspective view of its most prominent city.

When the pontiff commissioned the architect Domenico Fontana to repair the Claudian harbor, it was Danti who had furnished the necessary plans.

While at Rome, Danti had published a translation of a portion of Euclid with annotations and had written a life of the architect Jacopo Barozzi da Vignola, preparing also notes for the latter's work on perspective.

In recognition of his labors, Gregory, in 1583, had made him Bishop of Alatri in the Campagna.

Danti has showed himself a zealous pastor in his new office.

As bishop of Alatri, Danti has convoked a diocesan synod, corrected many abuses, and showed great solicitude for the poor.

Shortly before his death Pope Sixtus V had summoned him to Rome to assist in the erection of the grand obelisk in the piazza of the Vatican.

Besides the works already mentioned, Danti is the author of Trattato del'uso e della fabbrica dell'astrolabo con la giunta del planifero del Raja; Le Scienze matematiche ridotte in tavole, also a revised and annotated edition of La Sfera di Messer G. Sacrobosco tradotta da Pier Vincenzio Danti.

He dies at Alatri in 1586, only three years into his service.