This cover decorated with unusual mantra in Lantsha script and specific foliage on the upper part is dated 15th/16th century. Some examples from the 15th century show great similarities with the present lot. For a similar decoration with sanskrit characters, see a Xuande (1426-35) blue and white jar and cover from the Palace Museum illustrated in Blue and White Porcelain with Underglazed Red - The Complete Collection of Treasures of the Palace Museum, Hong Kong 2000, p.115, pl.109.
Sanskrit characters appear also on a number of Wanli (1573-1619) blue and white porcelains including a pair of flower-shaped dishes in the British Museum, illustrated in J.Harrison-Hall, Ming Ceramics in the British Museum, British Museum Press 2001, p.313, nos.11:101 and 102. For a similar shaped cover and finial, see the blue and white Xuande jar and cover from the Palace Museum and illustrated in Op. Cit., p.109, pl.103
The same floral decoration on the finial can be found on the blue and white cover of a Longqing (1567-72) teapot from the Palace Museum, illustrated in Op. Cit., vol.II, p.164, pl.153.