Mathematician, astronomer, Dominican friar and cosmographer. Pellegrino Rainaldi Danti aka Egnazio Danti (Perugia 1536 - Alatri 1586), as a child he learned the rudiments of painting and architecture from family members, but the vocation for mathematics and science soon became his destiny.

After studying philosophy and theology, he devoted himself tirelessly to mathematics, astronomy and geography.

In 1567 or so, Cosimo I de Medici, Duke of Tuscany called him in his court for developing and divulgate mathematical and astronomical studies in its territory.

He became a Grand Ducal cosmographer working on the maps that still decorate the Hall of charts in Palazzo Vecchio.

During his permanence in Florence Danti he lived at the convent of Santa Maria Novella installing the armillary sphere and the gnomon present the church's façade. The meridian line that you see inside the church today are based on the studies and the gnomic holes made by Danti in the last decades of the 1500s.

In his life he realized numerous scientific instruments and wrote many popular texts on the manufacture and use of the astrolabe and astronomy.

Meanwhile in Florence, the successor of the Grand Duke Francesco I broke off all relations with the Danti. Invited to Rome by Pope Gregory XIII Danti worked with great passion to maps of the Vatican Palace, becoming the pontifical mathematician and member of the commission for the reform of the calendar. Here also followed the works of painters summoned to the Vatican by the Pope, to continue after Raphael to draw up the maps of Italian territories.

Always in Rome Danti designed the reparations of the ancient port of Claudio collaborating with the great architect Domenico Fontana.

He published the translation of some of the works of Euclid and wrote the life of architect Jacopo Barozzi da Vignola. In recognition of his work, Pope Gregory XIII, in 1583, appointed him Bishop of Alatri in Lazio.

Danti was very active in his ecclesiastical activity, summoned a diocesan synod, he fought against abuse, showing great attention to the poor.

It was also a promoter and project manager of the Annunciation Monastery (now a national monument).

A few years after his death, Pope Sixtus V requested his presence to Rome to oversee the arrangement of the great obelisk in the Vatican square.

In his life he realized numerous scientific instruments and wrote many texts on the manufacture and use of the astrolabe and astronomy.

Egnazio Danti died of pneumonia at Alatri in 1586. After his death, to occupy his chair of mathematics at the University of Bologna in 1588 was named Giovanni Antonio Magini, favorite pupil of Galileo Galilei.