In the panel from Saint-Ouen, in Rouen, Bartholomew administers baptism to those who have accepted his teaching, beginning with King Polémius and members of the royal household. The scene is set beneath a tall, tiered Gothic canopy whose delicate silver-yellow tracery recalls the stone vaulting of the abbey church. The richly patterned damask background, painted in deep green and soft red tones, evokes the ceremony’s dignity and situates it within a luxurious, courtly environment.

At the centre, two newly converted catechumens stand within a large, tub-like baptismal vessel—an iconographic form typical of 13th–14th-century depictions of mass baptism. They are shown bare-chested, a convention used throughout medieval art to signify spiritual rebirth and the shedding of the old life. Their hands are joined in a gesture of humility and readiness, while their lowered heads emphasise the solemnity of the sacrament.

St Bartholomew, haloed and robed in warm ochres and deep blue, bends slightly forward as he pours water over the head of the foremost catechumen. His posture is careful and deliberate, the gesture clearly legible even through the dense leadlines of later restoration. His left hand supports the ritual action, while his right hand—still raised in a softened echo of the exorcistic gestures seen earlier—confers both blessing and instruction.

To the right stands a courtier or official, richly dressed in a fur-lined mantle and with headgear reflecting the medieval European imagination of “eastern” nobility. His presence affirms the royal endorsement of the new faith: this baptism is not simply a private conversion but the transformation of a court and, by extension, an entire people. His thoughtful gaze and dignified stillness provide a grounded counterpoint to the animated movement of the catechumens.

The overall composition, with its symmetry, ascending canopy, and clear vertical lines, reinforces the theological message of elevation and purification. The choice to depict multiple baptizands within a single tub aligns with the Legenda Aurea account, which emphasises that entire populations—rather than individuals alone—came to Christianity through Bartholomew’s preaching. The scene thus serves as the narrative and spiritual culmination of the cycle: following preaching, confrontation with false worship, and the healing of the king’s daughter, the apostle brings a new community into the Christian fold.

Although the lower portion of the panel shows signs of later replacement, the essential medieval artistry remains visible in the finely drawn faces, the rhythmic folds of drapery, and the interplay of warm ochre and cool silver-yellow. Together, these elements convey both the solemnity of the sacrament and the optimism associated with the foundation of a new Christian community.