(1724–87). Italian architect. He designed most of the Museo Pio-Clementino in the Vatican, a master-work of Neo-Classicism, which provides the settings for many of the greatest treasures in the papal collection. He redesigned the Cortile Ottagono (1771–3), the Sala Rotonda (c. 1776–80), the Sala a Croce Greca (c. 1776–9), the Sala delle Muse (c. 1781–2), and the new access stairs. In some of this work he collaborated with Camporese. His use of Antique elements and clear, logical, expression of structure gave his architecture great authority.
From A Dictionary of Architecture and Landscape Architecture in Oxford Reference.