The Diözesanmuseum, set in a historic building right next to the cathedral, holds the treasury of the Diocese of Limburg. It is a small museum but punches well above its weight, with reliquaries, illuminated manuscripts and liturgical objects spanning more than a thousand years.
The star exhibit is the Limburg Staurothek, a tenth-century Byzantine cross-reliquary in gold and cloisonné enamel that was made in Constantinople around 968 and looted during the Fourth Crusade. It is one of the finest pieces of Byzantine goldsmithing in Western Europe. The museum is open Tuesday to Sunday and combines well with a visit to the Dom.