History - In mandatis

Jul 27, 2025 (markvd)

terminus for PM 1981 differs, I'll add it separately.

sources
[{"chant_id":"10114","source":"7","page":"126","sequence":"2","extent":"1"},{"chant_id":"10114","source":"24","page":"304","sequence":"0","extent":"1"}]

version
Solesmes 1934, 1981