Luís Reis-Santos. Letter to Theodore Rousseau. August 9, 1962, judging from a photograph, attributes this panel to Frei Carlos, between 1520 and 1530; says he plans to publish it in his forthcoming book on the artist.
José Alberto Seabra Carvalho in Cores, figura e luz: Pintura portugesa do século XVI, Museu Nacional de Soares dos Reis. Exh. cat., Museu Nacional de Soares dos Reis. [Porto, Portugal], , p. 22, ill.p. 23 (color), identifies the creature at the bottom left as a conch, noting that it appears most frequently in the iconography of the Resurrection of Christ, or in funerary subjects, as a symbol of rebirth, in this case of the deacon saint into a new life in the kingdom of heaven; finds the attribution to Frei Carlos entirely convincing and links our panel with a group of works he produced for the Espinheiro monastery [near Evora], including a "Saint Anthony and the Infant Christ" in the Museu Nacional de Arte Antigua, Lisbon (inv. 64); notes that the Lisbon painting measures 173.5 x 74 cm and believes that our panel was cut on the right side and the figure of the saint was centered in the composition.