Compare slightly smaller dishes with the same decoration: in the Idemitsu Museum of Art, illustrated by Koyama, Chugoku Toji, vol. I, Tokyo, 1987, pl. 21; illustrated by H. Scott, The Golden Age of Chinese Art, The Lively T'ang Dynasty, Rutland, Vermont/Tokyo, 1967, pl. 83; by C. Riely, Chinese Art from the Cloud Wampler and Other Collections in the Everson Museum, Everson Museum of Art, 1968, pl. 20; and in Mayuyama, Seventy Years, Tokyo, 1976, vol. I, no. 279.
In 'Metalwork and Chinese Ceramics', PDF Monograph Series No. 2, London, 1972, Margaret Medley, p. 6, explains that dishes and plates with flattened rims, found both in silver and in stamped polychrome-glazed pottery, ranging from the late 7th-early 8th centuries, were inspired by Iranian metalwork. The author cites an example illustrated by J.J. Smirnoff in L'Argenterie Orientale, St. Petersburg, 1909, pl. 77.
The result of Oxford Authentication Ltd thermoluminescence test no. C112m29 (1 November 2012) is consistent with the dating of this lot.