Initially built as castle in the ninth century, was transformed under the dogeate of Sebastiano Ziani (1172-78) as dogal residence that also welcomed the Major and Minor Council and some offices of the magistracy. During the first years of 1300 it was enlarged and the works lasted until the 1463; the building, originally of Byzantine style, amalgamated the Gothic forms, that respected the initial configuration of the building in a series of full volumes to the superior plan, characterized by a full wall little with few windows decorated with geometric motives with white and pink stones, and empty to the inferior plan, characterized by a long series of columns, embellished by capitals ( sixteenth and fifteenth centuries ) that for the greatest part today are kept in the Museum of the Work of Building. The Building was victim of many fires (1484 and 1577, year when was destroyed the Room of the Major Council and with it the pictures of the greatest painters of the time) that they required the reconstruction of some parts of it ( work of Antonio da Ponte and Antonio Rizzo) respecting the original architectural aspect. Today it is used for expositions and it houses the offices of the Superintendence for the Venetian Environmental and Architectural Goods. The two façades that give on the dock and on the little square measure 70 meters; they have few ogival windows edged with precious balconies dating back to the first years of he ' 400 (Dalle Masegne) and of 1536 (Scarpagnino and Sansovino). From the ninth arcade of the loggia of the façade that gives on the little square that distinguishes itself for the red color of the marble of the columns, the sentences of death were read.