Kassopi the capital of Kassopean was built before middle of 4th century B.C. on a hill in the southern side of Zalogo.
Kassopi, the capital of Kassopean land, was built before middle of century B.C., and it was situated in 550-650 m. attitude, on a hill in the southern side of Zalogo as to be protected from Ilian colonists the valley on the south of the city.
The greatest period of the city was on the 3o century B.C. when a lot of public buildings and houses are constructed
On the inside of its polygonal walls 3,20 – 3,50 m. thick – there were two – storey houses, in building –blocks of 230 m2, all facing the south. They were all very well built, bearing functional architecture facing a street and linked with a common sewage system having a special covered gutter. The city was built according to the Ippodamian system with 20 parallel streets 4,20 m. wide - the so-called "stenopi" streets- having a distance of 30 m. between them and crossing other wider roads - the so-called "platies", of a 6m. width that formed about 60 blocks of flats. In fact it was a very impressive city. Among the ruins a building called Prytanio or Katagogio stands out (something like a hotel of those times), a building 30x30 m. of two floors on three sides, but of one floor on the fourth side so as to let the sunlight come into the house. There are also ruins of the Odeon (of 2000 seats) and the Theatre (of 6000 seats).
The city had 10.000 inhabitants. The city was destroyed by Romans (Aimukius Paulo’s) in 167 B.C. and was finally deserted by its inhabitants when they forced to settle in Nikopoli at the end of 1st century B.C
The most important monuments of the site are:
The North Stoa was built in the period of the Epirotan League (234/3-168 B.C.). It had a polygonal stone crepis and the superstructure was built of bricks in a timber frame. The north side of the stoa was supported by 17 buttresses. The interior was divided into two parts by a row of 13 square pillars, and the facade was formed by a colonnade of 27 Ionic columns. In front of the facade were preserved 21 stone bases with inscriptions dated to the 3rd and 2nd centuries B.C.
The Prytaneion and the West Stoa. The Prytaneion is located on the west side of the Agora. It had a central peristyle court with 3 x 4 Doric columns and six rooms arranged around it. On the east side was a stoa with 13 Doric columns while in front of the structure extended an open space (temenos) with bases and altars. The whole complex was destroyed by the Romans in 167 B.C.
The Katagogion was a public building, probably a guests' quarter, dated to the Hellenistic period. It has a peristyle central court, surrounded by four stoas with octagonal columns (7 x 8). In the back of the stoas are 17 rooms that do not communicate with each other. The building had a second storey with a balcony and was built on top of an earlier structure, dated to the 4th century B.C.
House 5. The house lies to the NE of the Katagogion and consists of a central court, an open courtyard, the men's quarters (andron), kitchen, baths and subsidiary rooms. It was destroyed by the Romans in 167 B.C. and temporarily repaired afterwards.