solid building which still stands. Return to Siena and Later Career (1485–1500) Letters from 1485 reveal that the Sienese government wrote to Francesco di Giorgio to request that he return to his native city and embark on the design and construction of public buildings. He did return to the city in 1486 and began receiving an annual salary of 800 florins for his position as official city engineer in which he would inspect all engineering projects throughout Siena. Di Giorgio also completed artistic projects for the city, such as the candle-holding angel sculptures which he contributed to the altar at the Opera del Duomo. This time was one of prosperity and popularity for Di Giorgio, whose presence and expertise were fought over by the rulers of several city-states, particularly Siena and Urbino. His tax documents from 1488 show material wealth as well as familial wealth in the form of six children. In 1490 he was commissioned by the government of Milan to produce a model for dome of the Milan Cathedral. This project led him to journey to the site of the cathedral, where he met Leonardo da Vinci who had also been hired to consult on the building. Di Giorgio apparently provided useful advice to the constructors of the cathedral, and was paid 100 florins for his trouble. His expertise as a war engineer came into play again during the Italian War of 1494–98, when he was in the employ of Ferdinand II of Naples. He used tunnels and explosives in what is considered the pioneering use of mining technology for warfare. In 1499 Di Giorgio was elected the capomaestro of the Opera del Duomo. Death (1501) Francesco di Giorgio died at the age of 62 outside Siena in 1501 or early 1502, having retired to the countryside mid-1501. His widow spent most of the rest of her life embroiled in legal battles related to the late architect's estate. See also Taccola, Sienese Renaissance engineer Notes Further reading Bertrand Gille, 1978. Les Ingénieurs de la Renaissance, Thèse Histoire, Paris, 1960. Seuil, in series Points Sciences) Marc van den Broek, 2018. Leonardo da Vincis Erfindungsgeister, Eine Spurensuche NA-Verlag Mainz, 2018. External links Browsable online archive of digitized images at Biblioteca Leonardiana (e-Leo) Palladio's Literary Predecessors Web Gallery of Art Biography on Francesco di Giorgio Martini The Gubbio Studiolo and its conservation, volumes 1 & 2, from The Metropolitan Museum of