The land where Prague came to be built has been settled since the Paleolithic Age. Several thousands of years ago, there were trade routes connecting southern parts of Europe to northern Europe which passed through this area, following the course of the river. From around 500 BC the Celtic tribe known as the Boii, were the first inhabitants of this region known by name. The Boii named the region Bohemia and the river Vltava. The Germanic tribe Marcomanni migrated to Bohemia with its king Maroboduus in AD 9. Meanwhile, some of the Celts migrated southward while the remainder assimilated with the Marcomanni. In 568, most of the Marcomanni migrated southward with the Lombards, another Germanic tribe. The rest of Marcomanni assimilated with the invading West Slavs. (The "Migration of Nations" started in the 2nd century; it ended at the end of the 9th and at the beginning of the 10th centuries). The Byzantine historian Prokopios mentions the presence of the Slavs in the lands in AD 512.
According to legends, Princess Libuše, the sovereign of the Czech tribe, married a humble ploughman by the name of P?emysl and founded the dynasty carrying the same name. The legendary Princess saw many prophecies from her castle Libusin, which was located in central Bohemia.[citation needed] (Archaeological finds dating back to the eighth century support the theory of the castle's location). In one prophecy, it is told, she foresaw the glory of Prague. One day she had a vision: "I see a vast city, whose glory will touch the stars! I see a place in the middle of a forest where a steep cliff rises above the Vltava River. There is a man, who is chiselling the threshold (prah) for the house. A castle named Prague (Praha) will be built there. Just as the princes and the dukes stoop in front of a threshold, they will bow to the castle and to the city around it. It will be honoured, favoured with great repute, and praise will be bestowed upon it by the entire world.