ELOW YOU WILL FIND seven (7) videos explaining the rhythm of the Editio Vaticana (Vatican Edition) created by Abbot Pothier at the request of Pope Pius X. Many people are confused about certain topics regarding Gregorian chant. Who was Dom André Mocquereau? Was he involved in editing the Vatican Edition? Are the Solesmes rhythmic signs official? Has the Editio Vaticana changed since 1908? These are but a few of the questions dealt with in these videos.