Final answer:
Claude-Nicolas Ledoux was a prominent Neoclassical architect known for the Main Entrance, Saltworks at Arc-et-Senans, an embodiment of Neoclassical architecture celebrated during his time for its classic forms and civic virtues.
Step-by-step explanation:
Claude-Nicolas Ledoux (B. 1736-1806) was an influential French architect during the Neoclassical period. His architectural masterpiece, the Main Entrance, Saltworks at Arc-et-Senans, designed between 1775-79, is a prime example of Neoclassical architecture. Neoclassical architecture is characterized by its classic forms, grandeur, and symmetry, which were part of a movement that sought to revive the principles of classical Greek and Roman art. This period celebrated civic virtue and patriotism, qualities that were deeply embedded in the grandeur of buildings such as those designed by Ledoux. Additionally, this era was marked by artists like Nicolas Poussin, who depicted clarity and order in his classical style paintings, and sculptors such as Jean-Antoine Houdon, who captured naturalism and classical dignity in his portrait busts without sacrificing the sitter's personality.