The free-standing 28.5 metre-high keep and defence tower was built near the Rhine by the Archbishop of Trier, Werner von Falkenstein, at the beginning of the 15th century. At that time, it served as a safeguard for the customs house and consolidation of the border line to the territory of the Electorate of Cologne in the North. The plastered drystone construction was erected in place of the Kettiger Turm, attested in 1298, and formed the beginning of a safeguarded boundary line from Weißenthurm to Mayen. The “wieße Thorn” (old German for white tower) safeguarded the customs barrier once located there together with the customs house and guaranteed the Archbishops of Trier the revenue of the customs for the land. Today, the tower serves more romantic purposes: weddings and functions can be celebrated here.