Recto: a composition study for S. Gennaro led to Martyrdom. Verso: a composition study for The Eruption of Vesuvius. Both are preparatory to the frescoes in the lunettes of the Cappella del Tesoro in the Duomo, Naples. Both drawings have been squared for transfer. 

In 1631 Domenichino was commissioned to paint a fresco cycle in the Cappella del Tesoro in the Duomo, Naples. The scheme included the painting of the three lunettes: these frescoes represent, on the entrance wall, The Eruption of Vesuvius; on the wall to the right of the entrance, S. Gennaro protects the City of Naples from the Saracens; on the wall to the left of the entrance, S Gennaro led to Martyrdom.  

The lunette of The Eruption of Vesuvius was the first of the frescoes in the chapel to be completed, details of the scene deriving, according to the biographer Giovanni Pietro Bellori, from Domenichino's observations during the eruption of 1631-2. Payment for this lunette and for the lunette of S. Gennaro led to Martyrdom is recorded on 26 November, 1633. These lunettes were probably designed concurrently. The lunette of S. Gennaro protects the City of Naples from the Saracens was completed by 12th March, 1637.