This work by Joan Mates falls within the framework of the International Gothic of the late 14th century at a time when most of the arts were influenced by both France and Siena, resulting in highly decorative works with subtle, delicate colouring. The first documentary reference to Mates, son of a leather worker, is dated 1391 and states that he was living in Barcelona. The fact that Mates’ name is associated in the document with that of the painter Pere Serra has led to the assumption that Mates may have trained in Serra’s workshop. The fact that they worked together is known, as after Serra’s death Mates completed the Saint Thomas and Saint Anthony altarpiece for Barcelona cathedral. Mates was a celebrated artist in his day and art historians have subsequently organised his oeuvre around three documented altarpieces: that of Saint Ambrose and Saint Martin in Barcelona cathedral of 1411, that of Saint Sebastian for the refectory chapel of the Pia Almoina in Barcelona of 1417–25, of which the central part survives (Museu Nacional d’Art de Catalunya), and the main altarpiece for the church Vila-Rodona of 1422. This was destroyed in 1936 but old photographs survive.
Saint John the Baptist and Saint John the Evangelist with a Donor entered the Thyssen-Bornemisza collection in 1955 and was catalogued until 1989 as the work of an anonymous International Gothic master. Prior to its acquisition, the painting had been studied by Mayer in 1921, who was the first to suggest a Catalan painter. Chandler Rathfon Post subsequently associated it with a group of paintings that he published as the “Peñafiel group”. These works were later attributed to Joan Mates. Mates located the two saints beneath two lobed arches. They can be identified by their attributes. On the left Saint John the Baptist has a closed book and a lamb, to which he elegantly points. He wears his traditional hair shirt, visible on his right arm but mainly covered with a fine blue and pink tunic held together at the shoulder by a twig. On the right and unusually holding a martyr’s palm is Saint John the Evangelist with the chalice in which the poison has already turned into a small dragon. At the feet of these two elegant figures is the kneeling donor. He is dressed in a costly style indicative of elevated social rank and has been identified as Henry V of England, leading to the suggestion that this work was by one of a group of English painters active in the early 15th century.
The panel may have been part of the central section of an altarpiece which also included the following episodes from the lives of the two saints: Saint John the Evangelist on Patmos (Musée Goya, Castres), The Birth of Saint John the Baptist, The Beheading of Saint John the Baptist, The Martyrdom of Saint John the Evangelist, and Saint John the Evangelist and the poisoned Chalice, in the Carreras Candi collection in Barcelona, according to Gudiol and Alcolea.