In November 1497, the French ambassador to the Holy See, Cardinal Jean de Bilhères-Lagraulas, commissioned him to carve a Pietà, a sculpture showing the Virgin Mary grieving over the body of Jesus. The subject, which is not part of the Biblical narrative of the Crucifixion, was common in religious sculpture of Medieval Northern Europe and would have been very familiar to the Cardinal.[38] The contract was agreed upon in August of the following year. Michelangelo was 24 at the time of its completion.[38] It was soon to be regarded as one of the world's great masterpieces of sculpture, "a revelation of all the potentialities and force of the art of sculpture". Contemporary opinion was summarised by Vasari: "It is certainly a miracle that a formless block of stone could ever have been reduced to a perfection that nature is scarcely able to create in the flesh."[39] It is now located in St Peter's Basilica.