Procession of Saint Januarius During an Eruption of Vesuvius is an 1822 oil painting by the French artist Antoine Jean-Baptiste Thomas. It depicts a procession of Saint Januarius, the patron saint of Naples, against the backdrop of the volcano Mount Vesuvius erupting. A major eruption of Vesuvius occurred from October to November 1822. This was reflected in a number of artworks of the era including Horace Vernet's Vesuvius Erupting.