This ancient Roman cup is an extraordinary example of silversmithing.
One of a pair, it was created in the first century A.D.
and dedicated to Mercury at a sanctuary in northern France.
It is one of the most exquisite pieces of Roman silver
to survive.
Ancient craftsmen employed a variety of sophisticated techniques
to produce the multiple components of the cup,
with its smooth inner liner,
ornate outer shell,
and cast handles and foot.
Many of these techniques are still
used by silversmiths today.
The smooth inner liner was formed
from a flat disk of silver.
The silversmith began by hammering
the center of the disk to create a rounded bottom.
Then, rotating the disk over an anvil or wooden form,
he hammered outward from the center to raise the sides.
Repeated hammering hardened the silver,
making it brittle and difficult to work.
To make it more pliable, the silver
was heated and then submerged in water to cool.
This process, called annealing, was repeated periodically
as the silversmith raised the liner.
Once the liner reached its full height,
it was turned on a wheel to smooth the surface
and refine the shape.
The rim was rolled outward to facilitate later assembly.
X-rays of this cup reveal that an inscription
was punched into the bottom of the liner,
recording its weight.
Never intended to be seen outside the workshop,
this inscription indicates careful control of the valuable silver.
The ornate outer shell was also raised from a disk of silver,
but was made slightly larger and with a flatter bottom than the inner liner.
The complex scenes on the outer shell
probably began as a drawing and a full-scale model
in wax, clay, or plaster.
The silversmith fashioned the three-dimensional decoration
by first working from inside, [hammer taps]
raising and shaping the general forms of the figures
with a rounded tool.
This process is called repoussé--
French for "pushed out."
[hammer taps]
To define the figures more clearly,
the silversmith then worked from the outside of the shell.
By working back and forth between the interior and the exterior,
the craftsman raised the scenes in relief
and added details.
[light hammering]
Certain elements of the decoration in especially high relief
were fashioned separately and attached as appliqués.
The handles and foot were also created separately,
perhaps by other craftsmen in the workshop.
Each handle was assembled from three parts cast individually
using the indirect lost-wax process,
which allowed multiple components to be
made from a single prototype.
From the prototype, a reusable master mold
was produced for each part.
Repeatedly filling the master mold with molten wax,
the craftsman made multiple identical casting models.
These were encased in clay and then fired,
which melted out the wax [fire roars]
and left a hollow casting mold into which silver could be poured.
After the silver cooled, the mold was broken open,
and the cast components were removed, separated,
cleaned, and detailed.
Once all the components were ready, the cup was assembled.
The craftsman inserted the inner liner into the outer shell,
interlocking their rims to form a smooth lip.
Then the handles and foot were soldered to the body.
This X-ray shows how the liner is suspended
inside the outer shell, and how all of the components fit together.
Finally, a mixture of powdered gold and liquid mercury--
called amalgam--was selectively applied
to the silver decoration.
Heated, the mercury evaporated, [fire roars]
leaving a thin coat of gold over the silver,
accentuating elements of the design.
The gilt cup was then burnished to a brilliant shine.
Now almost two thousand years old,
the cup remains a testament to the expert craftsmanship
of ancient artisans.