Its construction was extremely protracted, but as early as 1735 the architectural framework was complete, and by Salvi's death the ornamental rock formations and full-scale models of most of the sculpture were in place. The fountain is the most monumental water display in Rome and represents the culmination of a tradition of combining water and sculpture within an elaborate architectural setting. Salvi treated an existing façade of the Palazzo Poli as a nine-bay unit with the central three bays articulated with attached Corinthian columns suggesting an antique triumphal arch. The central bay is treated as a giant niche, which frames Maini's free-standing figure of Oceanus, from which the sculptural scheme and the waters of the fountain seem to flow into a large rock basin. An attic storey above the central niche is surmounted by a coat of arms of Clement XII and incorporates statues representing the Four Seasons, part of a complex iconographic scheme emphasizing the important role of water in nature. Giovanni Battista Maini executed the Oceanus group as drawings and models from 1734. His final full-scale stucco figures, later carved in marble by Pietro Bracci, were placed on the fountain between 1743 and 1759.