The manuscript includes Four-part vocal pieces for holy days of the church year, and it's numbered 542 in the catalog.
Prince-bishop Diethelm Blarer ordered Italian composer Manfredo Barbarini Lupo, from Correggio, composed these challenging vocal pieces, Father Heinrich Keller (1518-1567) wrote the text, and the manuscript illustrator Kaspar Härtli from Lindau on the northern side of the Bodensee illuminated the first pages with the important holy days of the church year.
Some of the sheets show an important number of birds, not to scale.
Source: Cod. Sang. 542, page 5, Stiftsbibliothek St. Gallen / Codices Electronici Sangallenses http://www.cesg.unifr.ch