"There is only one portrait of Canaletto that can be accepted as fully authentic. This is the engraving which appears with a portrait of Visentini as the frontispiece of the Prospectus Magni Canalis Venetiarum of 1735, and of the enlarged editions ( Urbis Venetiarum Prospectus Celebriores) of 1742 and 1751. Canaletto is seen head shoulders, within an oval enclosed by a carved frame ornamented with flowers and foliage, and inscribed below the portrait Antonius Canal/ Origine Civis/ Venetus. At the bottom of the frame is a shield with a chevron, The Canal coats of arms. In the lower left margin is the inscription Ex Monochromate Io. Bapt. Piazzetta; and lower right, Antonio Visentini Inv. Del. et Sculp. From the date of the first publication of the engraving, Canaletto as represented cannot be more then thirty-eight; and since there is evidence of that the plates for the Prospectus Magni Canalis were ready in 1730, he may well not be much more then thirty." - Constable, W. G. (1962). Canaletto (Vol. I). Oxford, England: Oxford University Press