This volume contains the first in the series of lavish choirbooks published by Adam Berg under the title Patrocinium musices. The first five books in the series, issued between 1573 and 1576, were devoted exclusively to religious music by Lasso and were subsidized by Wilhelm of Bavaria.

Patrocinium I includes twenty-one motets, seven each for four, five, and six voices. Lasso dedicated the book to Wilhelm in a long preface that glosses the illustrations in the title page and frontispiece, emp...