This ivory figure of the crucified Christ ultimately derives from a painted Crucifixion by Peter Paul Rubens of around 1610–11. The reverse of the tortoiseshell veneered cross contains, behind rock-crystal windows, a number of relics of saints, including the apostle Bartholomew, and the martyrs Romulus, Hippolitus, Eustachios, Barbara, Felix and Hilarius. Each is carefully labelled, as required by Church law after the Council of Trent. As objects for devotional contemplation, the relics ensure that the believer prayed to Christ in the company of the saints.