The Holy Thorn Reliquary belonged to Jean, duc de Berry.

Evidence

In the late fourteenth century one came into the possession of a powerful French prince, Jean, duc de Berry, and we can be absolutely confident that the reliquary in the British Museum belonged to him. — Neil MacGregor, A History of the World in 100 Objects, 1039

Categorization

• corroborated: 2 independent passages support this claim — Neil MacGregor, A History of the World in 100 Objects, 1039