The pottery kilns
Orvietan ceramic between the Medieval and Renaissance periods
The medieval Majolica* workshop
After kiln-firing, some ceramics were rejected because they had defects in their shape or decoration. These rejects are displayed along the walls, and next to some of them you will find reconstructions to show what the original items would have looked like.
A part of the room has been directly dug out from the tuff rock; the stone has become white due to prolonged heat exposure. That was the ceramic workshop’s kiln.
Some metal studs in the floor indicate the position of blocks of tuff and brick that were used to enclose the firing chamber.
The blocks would be partially heat-damaged, and the chamber would need to be reconstructed each time the objects were put into and taken out of the kiln.
The rectangular recess in the corner is the opening to a chimney and it leads up to a small alcove which acted as a valve, permitting the kiln to be cooled and the heat to be distributed to the rooms in which the newly made clay objects had been
left to dry.
*the term Majolica refers to Italian earthenware that has been opaquely glazed using a tin oxide and is usually highly decorated
The Renaissance muffle kiln
To give a better understanding of the main types and the variety of Orvietan medieval and renaissance ceramics, we have compiled a collection of fragments in the four display cabinets on the wall close to the kiln’s remains.
Some lusterware fragments and numerous original tools are also exhibited.
The ceramic finds
- Glazed ceramics (end of the 13th century): The objects were painted and then immersed in lead-oxide based crystalline, before being fired at approximately 920°C.
- Ancient majolica (14th century): After being first fired (about 970 ° C), the object was immersed in enamel (crystalline with the addition of tin oxide), decorated in green (copper) and brown (manganese) and then fired a second time (at about 920 °C).
- 15th century majolica: The same technique of the previous century; blue, orange and yellow were added to the green and brown decorations.
Variations: sometimes a zaffre blue relief was added; in some cases “false majolica” were produced, where the white enamel was substituted with liquid clay called slip, and following its decoration was covered in crystalline.
- Lusterware (16th century): After the second firing, the majolica was again decorated with gold and ruby red glazes, then fired a third time (about 750 ° C).
- Terracotta and stone moulds for shaping clay: head and tripod moulds in terracotta
- Tools for shaping clay using the wheel: terracotta and metal slats, engraving rollers
- Objects for ceramics decoration: metal salts for lustre, samples of frits [sand and lead mix for decoration]; ampoules for decorative oxides…
- Tools used in the second Majolica firing: terracotta nails used to support the first plate or bowl in each pile; terracotta tripods and fragments of cooking racks
- When the medieval kiln was unearthed in 1985, it demonstrated that Majolica production existed in Orvieto between 1400 and 1500 A.D., wrongly considered a dark age in Orvieto’s ceramic history.
- When the muffle kiln was unearthed in 1998, it shed new light on Orvieto’s ceramic history, demonstrating that Orvieto also produced lusterware.
- A comparative study of the fragments found in the Via della Cave district has shown that practically all of those originating from the right-hand side of the road date between 13th to 15th century AD when there was an extensive system of ceramic kilns from which goods were exported to the main Italian cities and abroad. The discovery of the “Cavajole” kiln has enabled the manufacture of many majolica wares to be attributed to Orvieto, whereas before they were thought to have been produced in Viterbo or Faenza.