last century BC (after 125 BC), the "castle" served as the acropolis of an oppidum (town) of the Celtic Boii. A great number and diversity of findings (including coins, house equipment, two Roman buildings, castle entrance gate etc.) testifies to this. The castle hill, which was situated at the Danube and thus since 9 BC at the border of the Roman Empire, was also settled by the Romans during the Roman Period (1st to 4th century AD) as findings of bricks of Roman legions (Legion XIII GAN, Legion X GEPF etc.) and some parts of architecture (a Roman figural relief, roof parts etc.) suggest. The developments in the 5th century (the time of the Great Migration of Peoples) are largely unclear. Slavs, Nitrian Principality, Great Moravia (500 – 907) The situation changed with the arrival of the Slavs in the territory of Bratislava. Initially, they partly used older Roman and Celtic structures and added some fortifications. Probably at the end of the 8th century (definitely not later than in the early 9th century), at the time of the Principality of Nitra, a Slavic castle with a wooden rampart was constructed with a huge area of 55,000 square metres. In the second half of the 9th century, at the time of Great Moravia, a palace of stone surrounded by dwellings and a big basilica were added. The basilica is the largest Great Moravian basilica from the territory of Slovakia, and the area of the castle is approximately the same as that of the Mikulčice site (the historical town "Moravia"), which is the most important Great Moravian archaeological site. Material from old Roman buildings was used to construct this Slavic castle in Bratislava. This could be a confirmation of the disputed statement of Aventinus from the 16th century, who – referring to lost sources – claimed that around 805/7 the Great Moravian prince Uratislaus (i.e. Vratislav) constructed today's Bratislava (Castle?) at the place of a destroyed Roman frontier fort called Pisonium, and the new settlement was named after him Uratislaburgium / Wratisslaburgium. Another probable fact is that around 900 the castle and the territory it controlled was given in fief to Predslav the third son of the Great Moravian king Svätopluk and that Pre(d) slav, or a person of the same name, is the person after which the castle and the town received its old German name Pressburg (from which the old