Sienese documentary art historian, editor of the the definitive Vasari Lives edition, founder of modern Italian scholarship of the Italian renaissance. Milanesi studied law, but never completed a degree. Instead, his talents at discerning Italian scripts and handwriting led him to the Biblioteca Comunale at Siena and the sources pertaining to art history. He set about transcribing and publishing with Lorenzo Ilari, an index to this collection, a project which he worked on throughout his life. In 1842 Milanesi joined the periodical L'Antologia, founded in 1821. Together with his brother, Carlo (1816-1867), father Vincenzo Marchese (1808-1891) and Carlo Pini (1806-1879), Milanesi 1845 founded the Società di Amatori delle Belle Arti. The group published a scholarly edition of Vite dei pittori by Giogrio Vasari from 1846 and 1870, exposing the numerous errors of Vasari in a systematic way. In 1848 he was named Ispettore of the Accademia fiorentina di Belle Arti. In 1854 Milanesi published his Documenti per la storia dell'arte senese the first in his series of published primary sources in Sienese art history largely from the Archivio dell'Opera de Duomo in Orvieto. Milanesi continued his series of documents, mostly on Siena and Florence art and artists. In 1856 he moved to Florence as the "resident academic" at the Accademia della Crusca. In 1858 was appointed Deputy Director of the Archivio di Stato in Florence and in 1864 succeeded the founder as editor of the guida dell'Archivio Storico. The same year he and Pini published a collection of artists' writing which included photographic examples of the script. He published an edition of the letters of Michelangelo in 1875. A second, nine-volume edition of the Vasari Lives appeared between 1878 and 1885 correcting errors of the first edition and including all known Vasari writings. Milanesi became Arciconsolo of the Accademia della Crusca in 1883. Finally, he was appointed Soprintendente degli Archivi Toscani in 1889, which he held for the next two years. Milanesi's publications form the starting point for modern Italian art history. His revaluing of Vasari was based in the Positivist belief that sources could uncover an accurate truth. The archival publications he wrote greatly supported the findings, among others of the American art historians Bernard Berenson and Richard Offner, who used his research extensively.
Documenti per la storia dell'arte senese, raccolti ed illustrati. 3 vols. Siena: O. Porri, 1854-56; edited, with Milanesi, Carlo, and Marchese, Vincenzo, and Pini, Carol. [first ed.] Le vite de' più eccellenti pittori, scultori e architetti. Florence: Società di Amatori delle Arti belle/F. Le Monnier, 1846-1857 [second ed.] Le vite de'più eccelenti pittori, scultori ed architettori seritte da Giorgio Vasari. 9 vols. Florence: G. C. Sansoni, 1878-85; edited. Buonarroti, Michelangelo. Le lettere di Michelangelo Buonarroti: pubblicate coi ricordi ed i contratti artistici. Florence: Le Monnier, 1875; edited. Cennini, Cennino. Il libro dell'arte: o, Trattato della pittura. Florence : F. LeMonnier, 1859; and Pini, Carol. La scrittura di artisti italiani (sec. XIV-XVII.). 3 vols. Florence: Presso l'editore, 1869-73.
Ladis, Andrew. "The Unmaking of a Connoisseur." in, Offner, Richard. A Discerning Eye: Essays on Early Italian Painting. University Park, PA: Pennsylvania State University Press, 1998, p. 5; Petrioli, Piergiacoma, ed. Gaetano Milanesi: Biografia e carteggio artistico. Siena: Accademia senese degli Intronati, 2005; Direttori dell' "Archivio storico italiano" http://www.storia.unifi.it/asidspt/DSPT/varia/direttori/milanesi.htm