History of Cologne (Cologne Tower), one of Cologne's most prominent highrises. Secondly, a permanent improvement in traffic infrastructure, which makes Cologne one of the most easily accessible metropolitan areas in Central Europe. Due to the economic success of the Cologne Trade Fair, the city arranged a large extension to the fair site in 2005. The original buildings, which date back to the 1920s, are rented out to RTL, Germany's largest private broadcaster, as their new corporate headquarters. A controversy started after Muslims in Cologne sought to build a mosque. Most important for the history of Cologne since the Middle Ages is the Cologne
Electorate of Cologne confused with the Roman Catholic Archdiocese of Cologne, which was larger and included suffragant bishoprics such as Liège and Münster over which the Elector-Archbishop exercised only spiritual authority (see map below). Cologne was the ancient Roman city of Colonia Agrippina in the province of Germania Inferior, and has been a bishop's see since Roman times. In 953, the archbishops of Cologne first gained noteworthy secular power, when Bishop Bruno was appointed as duke by his brother Emperor Otto I. To weaken the secular nobility, who threatened his power, Otto endowed Bruno and his successors in the bishop's see with the