What is the **liturgical**[i] **history** of the **Prayer to Saint Michael ** *(Oratio ad Sanctum Michael)* that was composed by **Pope Leo XIII **? ---------- [i] **Liturgical**, i.e., as part of the official public worship of the Church distinguished from private devotion. Cf. [CATHOLIC CULTURE > Catholic Dictionary > **LITURGY** ]

The US Census Bureau: [Easter Dates from 1600 to 2099 ](https://www.census.gov/data/software/x13as/genhol/easter-dates.html) describes the date of Easter from the years 1600 to 2099. There is a noticeable movement of the date from one year to another, ranging from the third week of March to the fourth week of April. Easter is celebrated on the first Sunday after the Paschal full moon (a mathematical approximation of the first astronomical full moon, on or after 21 March – itself a fixed approximation of the March equinox). This formula for deciding the date was fixed with a view to making Good Friday coincide with Nisan 14 on the Jewish calendar, the date on which Jesus was crucified. But the coincidence rarely happens. This year, Nisan 14 falls on Saturday, the 12th of April, whereas Good Friday falls on the 18th of April. My question is: Has the Catholic Church ever considered an alternative formula for deciding the date of Easter?