It was the great Doge Tommaso Mocenigo (1413-1423) who urged upon the Senate the necessity of completing the palace. In 1424 the work was begun. Progress was slow and was hindered by the usual fire, but gradually the splendid stone wall on the Rio del Palazzo side went up, and the right end of the lagoon facade, and the Giants' Stairs, and the Piazzetta facade, reproducing the lagoon facade. The elaborately decorated facades of the courtyard came later, and by 1550 the palace was finished. The irregularity of the windows on the lagoon facade is explained by this piecemeal structure. The four plain windows and the very graceful balcony belong to the Sala del Maggior Consiglio. The two ornate windows on the right were added when the palace was brought into line with this portion, and they are lower because the room they light is on a level lower than the great Council Hall's. The two ugly little square windows (Bonington in his picture in the Louvre makes them three) probably also were added then. When the elegant spired cupolas at each corner of the palace roof were built, I do not know, but they look like a happy afterthought. The small balcony overlooking the lagoon, which is gained from the Sala del Maggior Consiglio, and which in Canaletto and Guardi's eighteenth-century pictures always, as now, has a few people on it, was built in 1404. It is to be seen rightly only from the water or through glasses. The Madonna in the circle is charming. She has one child in her arms and two at her knees, and her lap is a favourite resting-place for pigeons. In the morning when the day is fine the green bronze of the sword and crown of Justice (or, as some say, Mars), who surmounts all, is beautiful against the blue of the sky. The Piazzetta facade balcony was built early in the sixteenth century, but the statue of S. George is a recent addition, Canova being the sculptor.