Quite when and why one of the quails turns blue is an open question; it is likely to have occurred in the 1720s. This was a very common and much imitated pattern. For Meissen variants on the pattern, see, e.g., Hetjens-Museum, 1997, pls. 104, 105.For a Bow jug and a Worcester bowl, cover and stand, see Porcelain for Palaces, 1990, pls. 371 and 372, and for a Chelsea teapot, see Porcelain for Palaces, 1990, pl. 367. For Chantilly variants, see Le Duc, 1996, p.83 (bottom), and Porcelain for Palaces, 1990, pl. 366.