A Song Mass in Siena

An unusual mass in a late 15th-century Sienese choirbook has attracted increasing attention in recent years, not least because of its possible authorship by Jacob Obrecht. A closer look reveals some compositional procedures not previously encountered anywhere in the period, as well as further evidence strengthening the attribution to Obrecht; the findings also shed some new light on the history and composition of the well known Lutheran choraleAch Gott vom Himmel sieh darein.