E. McGrath, Rubens, Subjects from History, Corpus Rubenianum Ludwig Burchard XIII, vol. 2, cat. no. 55 (5), as “Grisaille”; ; Justus Müller-Hofstede, who drafted a certificate for the painting, regards it as an authentic work by Rubens. The painting depicts an episode from Jabocus de Voragine’s ‘Legenda Aurea’. Few events in the early history of the Church have left such a profound impression as the public penance of Emperor Theodosius the Great before Archbishop Ambrose in Milan in 390. On Christmas Day 390, Ambrose prevented the Emperor from entering the Cathedral, since he disapproved of the massacre ordered by Theodosius in Thessalonica. According to the ‘Annales Ecclesiastici’ by Cardinal Baronius, the Emperor had to go back after Ambrose made clear to him that the power of the Church was much superior to the Emperor’s temporal power. The subject was rarely painted during the 17th century. This is surprising, since the scene is usually interpreted as the expression of the supremacy of the power of the Church over temporal power, which was one of the main concerns of the Counter-Reformation.; ; Little is known about the context in which the composition was executed or about the early provenance of the preserved versions. It can be assumed that studies, sketches and preliminary drawings must have existed in the workshop over a long period of time, if one takes the year 1605 (in which Rubens produced an altar for the Jesuit Church in Genoa) as the beginning of the work on this subject. In 1682, a version of the composition, or at least sketches thereof, must have been still available in the workshop, since some studies executed by his pupils, possibly after Ruben’s sketches, and dating from this year are still preserved today. In 1622 Rubens reportedly attempted to sell a painting with this subject (‘il suo Ambrogio’) to the art dealer Vivot for 200 livres. Since this would have been a very cheap price for a finished painting, the item in question was possibly an oil sketch as a ‘ricordo’, which may be identifiable as the present painting.; ; Two complete versions of the composition have been preserved, which were without a doubt also executed in the master’s workshop: one in the Kunsthistorisches Museum, Vienna (inv. no. 524), the other in the National Gallery, London. Today, scholars unanimously agree that, in the Viennese version, young van Dyck, working under Rubens’ supervision, completed an early sketch by the master, whereas the London version was first completed by van Dyck in Rubens’ studio and subsequently changed by van Dyck himself when he left the workshop. The present painting, probably a sketch executed by a student under Rubens’ guidance, does not match any of the known versions. Both the fact that the composition remained in the workshop for a very long period of time and the existence of numerous studies executed by students suggest that the present painting is probably the product of a studio assistant. Specialist: Dr. Alexander Strasoldo