My recent post on the repercussion has induced some to ask: “Can we just sing whatever rhythm we want for the Vatican Edition? What about mensuralism? What about Bonvin and Vollaerts?” For those of us who work in the Extraordinary Form, we must follow the rhythm of the Editio Vaticana, and this was addressed in the famous “Martinelli Letter” of 18 February 1910. You can download this letter, officially promulgated by Sebastiano Cardinal Martinelli (d. 1918), Prefect for the Congregation of Sacred Rites under Pope Saint Pius X.
Cardinal Martinelli was very important.