Domus Fulonica or the Textile Workshop is the name of the palace situated at the street of Via Principalis Superior, opposite of the Episcopal Residence.

The name stems from the discovery of shells in 1934, when it was excavated for the first time. The scholars believed that the discovered shells were used for the production of purple dye. This argument and the discovered spindle whorls were enough to determine the house as a Textile Workshop.

The new excavations during the ‘70s brought conclusions that rejected the former thesis. It was acknowledged that the building was a private house with two phases of construction, from the end of the 3^rd and the end of the 4^th century AD.  It was destroyed in the 5^th century, after what new modest houses were built on top of the ruins, incorporating some of the older walls. It was concluded that the discovered shells were common food and they are not the spondilus type used for purple dye. A ring with an inscription GR (ΓΡ) was discovered and some researchers suggested that the name of the building should be “House of GR”.

Beneath the whole complex there were Hellenistic graves discovered during the campaigns in 1975 and 2001. The deceased were cremated and their ashes were placed in graves with different shapes.

The house from the 4^th century is presented at the site nowadays. It has a peristyle surrounded by 12 columns with a well in the middle. All around the peristyle there are many different rooms. The most impressive is the apsidal hall with four niches once adorned with sculptures. The building was destroyed in the middle of the 5^th century and according to the finds of nomadic weapons it is generally held that the catastrophe was result of an attack by the Huns.