The paper focuses on the relief representing the 'Flagellation of Christ' by Francesco di Giorgio conserved in the Galleria Nazionale dell'Umbria and aims to clarify certain iconographical issues that have remained unexplored, but which might shed new light on the presence of great artists in Urbino at the time of Federico da Montefeltro. The unusual way of presenting such a familiar evangelical subject, with the mourning figures of Mary and Saint John the Evangelist in evoking already the conclusive phase of the Passion, also involved the presence of figures in the right foreground, placed in clear contraposition to the protagonists of Christ's martyrdom. We may infer that the figures are Barabbas, another prisoner and an armed soldier, according to an iconographical interpretation descending directly from the text of Matthew's Gospel. This rare though not exceptional iconography of the episode recalls another fundamental work, Piero della Francesca's 'Flagellation' of the Galleria Nazionale delle Marche in Urbino. Without wishing to enter into the obscure significance of this twofold version of the evangelical subject present ab antiquo in Urbino, we would affirm an entirely evangelical interpretation for Piero's painting too, and the tendency of Francesco di Giorgio to make sometimes cryptic those historical or evangelical subjects which had been elaborated in the humanistic environment of the Urbino court.