The image of Christ´s precursor occupies the center of the panel with an iconography consistent with Medieval tradition. The strong lighting of certain parts of his elongated figure reflect the painter´s interest in an incipient chiaroscuro and the similarities to El Greco´s models suggest he was trained in beginning-of-the-century international mannerism.

The saint wears a short leather tunic and robes, both tied with a rope in a manner that became customary in the 14th century. At his feet, we see the lamb that alludes to Christ, and in his left hand, the cross and scroll bearing the inscription Ecce Agnus Dei. The landscape in the middle ground recalls those of Bassano, and the composition closes with a backlit tree at the right side.

This painting associated with the circle around Tristán, entered the Prado from the Museo de la Trinidad. Cruzado Villaamil considers it the work of an unknown Italian painter, but Sanchez Cantón, who confirms Cavestany´s suggested date of around 1626, attributes it and its companion, Mary Magdalene (P01309), to Loarte, due to its stylistic similarities with a Saint John the Baptist from the Convent of the Slaves of the Sacred Heart in Madrid, which was signed and dated that year. Pérez Sanchez, however, was not convinced by this attribution.

Pintores del reinado de Felipe III, Madrid, Museo del Prado, 1993, p.112, n. 38