The central painting of a series of 12 composing an Apostolate, produced at Zurbarán’s workshop, and with a life-size representation of the saints, this is the only one that is signed and dated by the artist (Fran.co de Zurbaran faciebat, 1633). Affirming the unity of the dogma, as a symbol and mirror of the triumphant Church in a period when the Counter Reformation was still in progress, this group of paintings was destined – perhaps at the behest of King Filipe IV (Filipe III of Portugal) – for the Monastery of the Canons Regular of São Vicente de Fora, in Lisbon, also during the 1630s.

Zurbarán was capable of investing even the most banal religious themes with a prodigious sense of the pictorial values of light. In this group of paintings, the source of the light that illuminates each of the characters remains invisible (the light always falls in a more or less oblique fashion from the upper left corner of the composition), except in the case of St. Peter, where the light falls vertically, in the centre, over the figure, underlining the tormented attitude of contrition displayed by the prince of the apostles and conferring upon the representation a sense of narrative that is not found in the other paintings.