The subject portrayed is a Roman legend related, with variations, by Titus Livy (Ab urbe condita, 2, 12 -13), Valerius Maximus (Factorum et dictorum memorabilium, III, 3. 3. 1.) and Plutarch (Paralella minora, 2, with Agesilaus). Porsenna, King of the Etruscans, besieged Rome and, in an attempt to save the Republic, Caius Mucius entered his camp for the purpose of assassinating him. But by mistake he killed one of his secretaries. When he was arrested, he showed his courage by thrusting his right hand into a lighted brazier and letting it burn, while declaring that four hundred Romans were ready to do the same thing in order to save their city. Porsenna was astonished, pardoned him and made peace. From that time on Caius Mucius was surnamed “Scaevola” or “left-handed”. This incident, taken to be an example of heroism and other virtues, was disseminated through illuminated mediaeval manuscripts and then served a model for many paintings, drawings and engravings in the 16th and 17th centuries, and even later.
This painting is certainly by the Dane Eberhart Keilhau, since it carries his signature. He was especially influenced by Domenico Fetti, from whom he learned vibrant brush strokes, picturesque realism and how to portray many human types. In 1656 he established himself in Rome, where he lived until his death.
The work shows features proper to this Danish painter: medium size, landscape format, compact composition with various half figures and an open background. More important is the realism of the figures (which even borders on vulgarity in the main character), the faces even more serious than the story tells, the simple gestures, without brusqueness, the sober agreement between warm colours – somewhat reminiscent of Rembrandt – and others, such as in the hero’s cloak, which are cold and of Venetian origin, and the lights and background lights derived from evolved Tenebrism.