This painting, long thought to be a portrait of Rudolf II (1552-1612) by Alonso Sánchez Coello, was identified as a portrait of Rudolf's younger brother Ernst (1553-1595) in the early 1960s (G. Heinz, 'Studien zür Porträtmalerei,' p. 114). It was one of three portraits of the sons of Maximilian II painted by Martino Rota in Vienna around 1580. The portrait of Maximilian III (1558-1618) is now in Vienna (Kunsthistorisches Museum) and the portrait of Rudolf II (1552-1612) is thought to be lost. DaCosta Kaufmann has described Portrait of Archduke Ernst as one of Rota's finest works and it certainly displays both the artist's talent for portraiture and his facility with the elements that make up court imagery (T. DaCosta Kauffman, op. cit., Chicago, 1988, p. 29). Indeed, Rota's training as a printmaker can be seen in his schematic treatment of fabrics and his focus on the engraved portions of Ernst's armor. The dating of the portrait to around 1580 on stylistic grounds is supported by the fact that Ernst was made regent of Inner Austria during that year and a portrait of this type would have been appropriate to commemorate his appointment. Three bust length portraits of Rudolf II, Ernst, and Maximilian III by Rota, all in the Kunsthistorisches Museum, Vienna, are thought to be reduced versions of his three-quarter-length portraits.