Which series of the Repertoire International des Sources Musicales contains the largest portion of materials?

The correct answer is Series A/2, which contains the largest portion of materials in the Repertoire International des Sources Musicales (RISM). Series A/2 focuses specifically on music manuscripts and printed music from a wide range of historical periods and regions, making it a significant resource for music scholars, researchers, and educators. This series captures an extensive amount of primary source materials, including both well-known works and lesser-known compositions, thereby providing a comprehensive view of the musical heritage represented in various sources.

Comparatively, other series are more specialized or focus on narrower subsets of the music repertoire. For instance, Series A/1 may deal with a specific aspect or type of music, while Series B and Series C focus on different categorizations or geographical regions that do not encompass as broad a range as Series A/2. Consequently, while all series within RISM serve valuable purposes, Series A/2 stands out due to its extensive collection, contributing significantly to the overall richness of the available musical sources.