The origin of the "black jack" goes back to the Crusades, when waterproof leather bags joined
by the neck, were referred to as "drinking vessels".
The leather, soaked in hot water and then dried, is known as "Jack" leather -
(also the origin of the modern word "jacket").
Jacks were originally black because the black material used to line the inside.
They were referred to simply as "Jacks" the until 1567,
when Corpus Christi College, Cambridge,
purchased a "black jack" for one shilling -
the word "black" possibly to distinguish it from the leather jerkin -
a man's sleeveless close fitting jacket, generally made of buff leather.
Laws passed by various English monarchs, from Edward II to Elizabeth I,
placed high export tariffs on leather, resulting in a price reduction on the material, and
making it the material of choice for drinking vessels and the transportation of liquids.
The leathern vessel retained its high place in both taverns and homes for many centuries.
"Every man of substance took his meals in his hall with his family and servants…. "
When the more luxurious 18th century dining fashions arrived,
"the lord took his meals privately in parlour or dining room,
and the leathern pot remained in the servants' hall -
with the exception of those that were silver mounted.
These latter were smaller as a rule and more richly treated;
they were edged with silver and often lined with that metal or with pewter
in the seventeenth and eighteenth centuries - and were highly prized."