From the very beginning, one of the most important and ambitious goals of the MAMS collection has been publication of the collected works of Iacobus Handl-Gallus in a modern transcription tailored to the needs of contemporary performers. The publication of his famous collection of motets, Opus musicum, consisting of four books containing a total of 374 motets, partially achieved this goal in 1990. The transcriptions and critical commentaries were prepared by Edo Škulj, and Gallus’s motets were published in thirteen volumes between 1985 and 1990. The edition is enriched by numerous facsimiles from Gallus’s original prints, published between 1586 and 1590 by the Prague printer Georg Nigrin (Jiří Černý).

Gallus assigned the fourth book of his Opus musicum (1590) to feasts of the Virgin Mary, the Apostles, the Martyrs, the Witnesses and the Holy Virgins. Gallus arranged the motets not according to the chronological order of the church year, but according to the number of voices. The first volume (IV/1) consists of 8-part motets for the feasts of Mary and the Saints.

The 2024 digitized post-edition is accompanied by a new preface and an introductory study by Dr Marc Desmet that summarizes and compiles all recent findings about the composer and his work.