Baldassarre Lanci (1510–1571) was an Italian architect, inventor, theatrical set designer, and master of perspective of the Renaissance period. Born in Urbino, he spent most of his working life in Tuscany. Early career He began his career as military engineer, for ten years following 1547 he was in the continual employment of the Republic of Lucca. His notability as a construction engineer earned him the commission to carry out a detailed survey of Rome's city walls and those of the bastions at Ancona, Civitavecchia and Ostia, and for Pope Pius IV Medici architect From 1557 he worked almost exclusively for Cosimo I de' Medici, Lanci's chief employer and patron for whom he supervised such projects as the fortification of Siena and many other Tuscan towns. His urban works included the design of Terra del Sole a fortified new city for Cosimo I de' Medici, in what is now the Province of Forlì-Cesena. Lanci also designed the church of Santa Maria della Rosa in the spa town of Chianciano Terme, in today's Province of Siena; Santa Maria della Rosa was built on a central plan; even though it was not finished, the church is notable for the sobriety, and clean lines of its design which culminates in an elegant dome. The church, however, was never fully completed. In 1585 building work stopped, fourteen years after Lanci's death. He also designed the walls of Grosseto in 1564, directing the construction site until his death in 1571, when he was succeeded by his son Marino. Lanci's most notable achievement was his invention in 1567 of a piece of surveying equipment to obtain perspectives with a visual field of 180°. The instrument, which he named distanziometro ("distance meter"), was made of a circular bronze plate placed upon a horizontal tripod the height of which could be adjusted. Semi-cylindrical paper was wound around its edge. A cylindrical eyepiece was placed in the centre with a retracting metal needle or pen underneath. The eyepiece was high enough to overlook the semicircle of paper and sight points of interest while the retracting needle scored on the paper to accurately plot the subject. It could also be used as a quadrant for measuring height in much the same way as the orizzonte designed by Leon Battista Alberti. His diverse works also included many aquatic projects such as the improvement of Livorno harbour (1566-1567), and the Sovana aqueduct, earning