On the back of the canvas we read that “Cesare Ligari son of Pietro painted this, in Venice, 1740”. The work was donated to the Ambrosiana by a descendant of theirs, Angelo Ligari. The painting shows the episode described in the Book of Numbers (Nm 21: 4-9): God sent poisonous serpents to punish the Israelites for their lamentations and, when Moses begged him to put an end to the massacre, the Lord ordered that a copper serpent should be raised up on a stake: all those who were bitten by a serpent would be saved if they looked at the effigy. In Christianity, the episode became an antitype of the Cross of Christ: just as one was saved by looking at the serpent, so one would obtain eternal life by looking at the Cross. This painting takes from a frieze painted in 1735 by Giambattista Tiepolo for the church of Santi Cosma e Damiano in the Giudecca, now in the Gallerie dell’Accademia in Venice.