In the Très Riches Heures a series of little weekday offices follows the Office of the Dead. Each day is devoted to a particular cult: Sunday to the Trinity, Monday to the dead, Tuesday to the Holy Ghost, Wednesday to the saints, Thursday to the Holy Sacrament, Friday to the Cross, and Saturday to the Virgin.

This entire section was without miniatures at the time of the death of the Limbourg brothers and the Duc de Berry; it was completely illuminated seventy years later by Jean Colombe.

For the Sunday Office of the Trinity, the artist painted the Baptism of Christ in an attempt to represent the words of the first Gospel: "And Jesus being baptized, forthwith came out of the water. and lo the heavens were opened to him... And behold a voice from heaven, saying: This is my beloved Son, in whom I am well pleased." (Matthew III: 16-17)

Jean Colombe has executed this scene with as much meditative simplicity as he could. Although Christ's slightly inclined body and the gesture of His right arm still betray a certain mannerism, the artist was no doubt trying to express the emotion with which Christ heard the words from above.

He stands with only His feet touching the waters of the River Jordan, while John the Baptist pours baptismal water from a shell onto His forehead. 

To the right, holding Christ's garments, are two angels of a type which are inspired by Byzantine mosaics and had already appeared in thirteenth century psalters.

The heavens have opened to reveal God within a circle of light and fire; a dove descends toward Christ to unite Him with His Father and thus completes the image of the Trinity.

In the middle ground, a crowd attracted to the desert by John's preaching witnesses the event with astonishment and admiration.

In the background is a town and one of the pleasant landscapes which Jean Colombe varied so admirably and which give his compositions special charm.