This leaf, large and richly decorated, comes from a choirbook made (or completed) in 1550, a late date for a manuscript given the rise of printed books since the end of the 15th century. The fact that one asked for an illuminated manuscript at this time indicates the original patron's pronounced taste for the meticulous work of scribes and illuminators. This manuscript was likely produced in a monastic environment, as religious communities continued to value illuminated manuscripts well after the advent of printing. 

This illuminated leaf contains both text and a musical score, allowing us to place this folio at the beginning of the Commune Sanctorum, in the Temporale section. It features a sumptuous historiated initial "B" introducing the chant Benedicat nos Deus (psalm 66:7-8) recited on the first Sunday after Pentecost to celebrate the Trinity, which is depicted in the initial. 

The depiction of the Trinity in the initial "B" follows the traditional Throne of Grace (Gnadenstuhl) motif, showing God the Father crowned on a heavenly throne, supporting the Cross with the crucified Christ, while the Holy Spirit is represented by the radiant dove. The leaf is also decorated with elaborate floral motifs in the margins, with putti playing among the foliage. The lower margin, two naked putti playing, while in the left side margin, one putto climbing, another supports a cartouche with the date 1550, and a third, dressed, supports the initial. 

The stylistic study of this illumination, with its saturated colors, free and lively brushwork, and exuberant forms, suggests that the leaf originated from Southern Germany, likely from Nuremberg, Augsburg or Constance. Certain stylistic elements recall the work of the illuminator Nikolaus Glockendon, one of the leading German artists of the first half of the 16th century and who had a prominent clientele, including Cardinal Albert of Brandeburg (1490-1545), for whom he painted, in collaboration with the famous Simon Bening, his Prayerbook (Kassel, Universität Kassel, 4° Ms. math. 50). 

As our illuminated leaf is realized after Nikolaus Glockendon's death, it is safe to attribute it to a talented follower of the great German artist. Since that this leaf originated from a choirbook likely intended for a monastery in Southern Germany, it is relevant to mention the monastery of Salem, near Constance. It is possible that the choirbook from which our page comes was made for this monastery.