The oldest name for Cheb comes from the Celtic name for the river Ohře – Agara, which was changed to the Latin name Egire, later derived into the German Eger. The Czech name Eger came in the early Middle Ages and meant the curve of the river in the northern part of the town, around the rock with the castle. The strategic rock is a place where a Slavonic settlement dating to 9th and 11th centuries was found. The original Slavonic settlers were pushed away during the 12th century during the strong German colonisation lead by the Bavarian houses of Vohlburg and Štauf. Emperor Fridrich II Barbarossa had his fort built in Cheb to emphasize its strategic importance on the frontier. The town of Cheb itself quickly developed from the former merchant village by the castle into one of the largest towns of the Middle Ages. The strategic position of the town as an intersection of long distance roads from Bohemia, Bavaria and Saxon secured prosperity of the region but also broght along military problems.