These were often used as witch bottles as their severe bearded faces were intended to scare off evil.
Witch bottles were popular in the seventeenth century to protect against evil spirits or counteract witches spells.
They would be filled with objects like hair, urine and magical charms then buried under the fireplace, floor or plastered inside walls.
When buried the bottle would capture evil and the house or person be protected as long as the bottle remained hidden.
The popular alternative name “Bellarmine” is recorded earliest in 1634, and is in popular tradition associated with the cardinal Robert Bellarmine (1542-1621), a fierce opponent of Protestantism in the Low Countries and northern Germany.
The reason for the association with Bellarmine is not entirely clear but was possibly conceived by Dutch and English Protestants to ridicule the cardinal, another possibility is his anti-alcohol stance.
This jug can be seen on display in the Jacobean House in Lark Hill Place at Salford Museum & Art Gallery.