The octagonal chapel was created as a total work of art, bringing together architecture and sculpture, and was constructed using the most costly and durable materials. The funerary function was reduced to a minimum, with a few inscriptions and the personification of the virtues, but no commemorative portraits.

Access to the chapel is via a rectangular vestibule with a sumptuous gate. In the Italian tradition, the gate signalled the private nature of the chapel, whilst still enabling the believer visual access to the representation of Saint Ursula.

The interior of the Saint Ursula Chapel is entirely clad in black Namur or Dinant marble, which is exceptionally well suited for a funerary chapel, but has not been used as coherently or in such great quantity anywhere else in Europe. The prestigious Carrara white marble used for the statuary provides a strong contrast, while the whole forms a remarkable harmony, architecturally, sculpturally and iconographically.