The Guelph Treasure (German: Welfenschatz) is the collection of medieval ecclesiastical art originally housed at Brunswick Cathedral in Braunschweig, Germany. Most of the objects were removed from the cathedral in the 17th century and dispersed in the 1930s. The Treasure takes its name from the princely House of Guelph of Brunswick-Lüneburg. The Guelph Treasure passed from Brunswick Cathedral into the hands of John Frederick, Duke of Brunswick-Lüneburg, in 1671, and remained in the Court Chapel at Hanover until 1803.