This drawing is part of a series by Giambattista after a bust of Giulio Contarini (circa 1500-1580) by Alessandro Vittoria (1525-1608). Vittoria was born in the Veneto and trained with Jacopo Sansovino. Contarini was a Procurator of San Marco and a patron of the arts. The sculpture (fig. 1) which Giambattista and his son Domenico depicted in at least a dozen other chalk drawings was and remains in the church of Santa Maria del Giglio in Venice. Tiepolo drew the bust from the front, right and left three quarter view, profile and even from the back of the head. All are executed in chalk, but several are more summarily described than others where there is a rich build up of the red and white chalk. Some of these more rapidly executed sketches were attributed to Domenico by Knox and Martin in their 1987 Master Drawings article (op. cit., pp. 159-60).
George Knox (op. cit., 2000, pp. 40-1) has convincingly shown that Giovanni Battista executed his drawings not after the marble but after a terracotta bust, recently acquired by the National Gallery of Canada (fig. 1; see exhib. cat. Salander-O'Reilly, 2000-1, pp. 12-28). The terracotta bears an inscription that incorrectly identified the model as Titian, an identification Tiepolo most likely assumed as well when he executed the drawings. Giambattista's drawings after Vittoria's sculptures are one of several examples of Tiepolo finding inspiration from earlier artists -- both painters and sculptors. Tiepolo made drawings of another portrait bust by Vittoria, this one of the artist Palma Giovane (a terracotta version of which is in the Kunsthistoriches Museum, Vienna). There are also several drawings after Antique sculpture (Knox, Giambattista and Domenico Tiepolo. A Study and Catalogue Raisonné of the Chalk Drawings, Oxford, 1980, K.6-9, M.260, 272, 459, 527, 655, 661, 67-82). In addition, Tiepolo executed drawings after paintings by Veronese, Peter Paul Rubens and Guido Reni (Knox, 1987, op. cit., pp. 158, 162, notes 3, 4).
Knox and Martin date the Contarini drawings to around 1742-3 based upon comparison with the Palma Giovane sheets and similar heads found in paintings by Tiepolo from the 1740s.