Dated from between 1627 and 1632, this painting, painted for the Cathedral of Reggio Emilia, marks the end of the first of Guercino’s mature periods, where the artist shows a taste for Venetian painting and a clear interest in Caravaggio. The subject matter is very rare in western painting as the John and Paul here are not the Evangelist and the Apostle but two brothers martyred in 363. The artist prepared his composition with great care, sketching many preparatory drawings, in which the extreme violence is unlike anything actually shown in the final painting. The calming presence of the Virgin and Child actually softens the vision of the decapitated head of one of the martyrs. The poetry of the ruins beneath a segment of blue sky is very much representative of Guercino’s genius.