Near the end of the project Brown turned his attention to completing the two spandrel figures in his picture 'Wycliffe reading his Translation of the Bible to John of Gaunt in the Presence of Chaucer and Gower' (1848, oil on canvas, Cartwright Hall Art Gallery, Bradford). His diary entry for 28th February records that he changed his mind about one of them settling on a 'young girl instead of a child to impersonate the Protestant faith.' On the same day he 'composed the other figure of Romish faith, a figure holding a chained-up bible and a torch - with a hood like the penitents at Catholic funeras showing only the eyes, with burning fagots and a weel [sic] of torture or accessories (Virginia Surtees, ed., 'The Diary of Ford Madox Brown,' p. 32). This figure can be seen in the oil sketch for Wycliffe reading his Translation of the Bible (Cartwright Hall Art Gallery, Bradford). It was not until the end of March that Brown began to draw the cartoons for 'the symbolic figures in the spandrils' and at this point he redesigned them. He altered the figure of Catholicism, omitting the wheel and replacing the torch with a crucifix. He also decided to set the figures in roundels and surrounded the medieval scene with elaborate Gothic architecture similar to that in 'The Seeds and Fruits of English Poetry' (ultimately called 'Chaucer at the Court of Edward III'). He completed the cartoons for both figures in just over a week. According to his diary Brown had Miss Wild to sit for the figure of Protestantism and used Maitland's head for Catholicism (p. 37).

The two cartoons reveal that Brown was under intense pressure to finish the painting on time. The majority of the drawing for Catholicism is highly finished in black chalk but the edge of the book and the chain have been finished much less carefully in sepia ink. Likewise the cartoon for Protestantism is highly finished except the lily which is barely drawn in. Perhaps because he was running out of time Brown decided to deviate from his usual practice of tracing his figures onto the canvas before painting them and 'determined to make the figures fill up the whole of the spandrils without tracery work.' In order to do this he 'squared the monk & drew him in on the Canvas' (The Diary of Ford Madox Brown, p. 36). The lines he used to square up the cartoon are still visible on the drawing. The effort of finishing the work took its toll on Brown and he had to ask his friend Charles Lucy to draw the figure of Protestantism onto the canvas because he was having problems with his eyes, a complaint he makes several times in the diary and no doubt due to the punishing hours he put in near the completion of a painting.
LM