This style of ewer was popular throughout the Qing dynasty, particularly in the Qianlong period, and imitates early 15th century prototypes. The intricate form of this ewer is derived from Near Eastern metalwork with which the Chinese came into contact through trade and exchange of exotic objects in the late Yuan and early Ming periods.
For an example of the Ming prototype of this exact design, see J. Ayers and R. Krahl, Chinese Ceramics in the Topkapi Saray Museum, Istanbul, 1986, vol. II, no. 618.
A very similar ewer and cover, also with Daoguang mark and of the period, sold at Christie's, London, 12 July 2005, lot 172.