This painting was first attributed to Cecco del Caravaggio by Joan Ainaud de Lasarte in 1947. At that time, very little was known about this painter, who was later identified as Francesco Buoneri, an artist working in Rome during the second decade of the seventeenth century who had previously been the most outstanding follower of Caravaggio. His relationship with the latter may also have been more than purely professional. Buoneri´s oeuvre influenced certain Spanish painters who were active in Italy during the early decades of the seventeenth century, including Juan Bautista Maíno (1581–1649) and Pedro Núñez del Valle (c.1597–1649), to whom some of Buoneri´s works have occasionally been attributed. Ainaud de Lasarte has indicated that this work may have been part of a larger composition that was cut down at some point, or that it may have been conceived in relation to another contiguous painting, as there must be a reason why all of the figures are looking to the viewer´s left and why their gestures point in the same direction. Given the dimensions of the Museo del Prado´s work, if the first hypothesis were true then the original painting would have been unusually large; it seems more likely that the work was one of the lateral paintings from a triptych. At the top, a guardian angel points with his right hand towards what must have been the centre of the once-adjacent composition. According to tradition, the guardian angel accompanies and protects a specific person whose soul is depicted in this work as a nude youth embracing the angel. Devotion to guardian angels is rooted in the Middle Ages, but was encouraged during the Counter-Reformation to combat Protestant invectives, and was finally made official by Pope Clement X (r. 1670–76). Kneeling below the angel, Saint Ursula is identified by her iconographic attributes: the arrow through her throat, and her standard. The story of her martyrdom alongside the eleven thousand virgins by the Huns near Cologne first appears in Geoffrey of Monmouth´s Historia regum Britanniae (History of the Kings of Britain), c.1130–36, but was later popularised by Jacobus de Voragine´s Golden Legend (c.1250). The man at Ursula´s side has customarily been considered to be Saint Thomas, although the fact that his only iconographic attributes are a halo and a book suggests he could just as well be any other of the Twelve Apostles, or even one of the Evangelists (Riello, J.: Italian Masterpieces. From Spain´s Royal Court, Museo del Prado, 2014, p. 126).