It is considered certain that the city founded by Kassandros in 316 BC was located on the site of the Thracian city Therme, mentioned in written sources since the 5th century BC. The only archaeological finds from Therme were discovered around 1930 during an excavation at the junction of Krystali and Antigonidon Streets and belong to the temple of Thermaios Dionysus. These are the only remnants of the Thracian predecessor of Thessaloniki, while a Macedonian tomb and parts of fortification embodied in the walls represent the Hellenistic city. During the Roman period, the city was expanded through the erection of many public buildings, thermae and temples, while the Agora, consisting of two continuous squares was founded in the mid-2nd century AD. The entrance to the lower square was decorated with sculpture reliefs, preserved today in the Louvre and known as “incantada”. During the years 1963 to 1971 the Odeion, the eastern stoa and a double cryptoporticus on which the south stoa is based were excavated in the area of the upper north square. Around 303 to 311 AD Thessaloniki became the capital of Galerius, one of the tetrarchs, who embellished the city with fine monumental edifices: the hippodrome, the palace, an octagonical public building, nymphaea, a triumpant arch and last but not least, the Rotonda, the official imperial church.