Ranking of liturgical days in the Roman Rite

The Ranking of liturgical days in the Roman Rite is a regulation for the liturgy of the Roman Catholic church. It determines for each liturgical day which observance has priority when liturgical dates and times coincide or "occur", which texts are used for the celebration of the Holy Mass and the Liturgy of the hours and which liturgical color is assigned to the day or celebration.

Ranks

Each day in the Catholic liturgical calendar has a rank. The five basic ranks for the Ordinary Form of the Roman Rite, in descending order of importance, are as follows:

All holy days of obligation are also solemnities; however, non all solemnities are holy days of obligation. For example, The Nativity of the Lord Jesus Christmas 25 December is a solemnity which is always a holy day of obligation, whereas the Nativity of Saint John the Baptist 24 June is not a holy day of obligation.

Inlocales,days which are celebrated as feasts or memorials in most of the Church are celebrated as solemnities; for example, St. Patrick's Day is a solemnity in Ireland, but is normally a memorial for the rest of the Church; Our Lady of Sorrows is a solemnity in Slovakia, whereas this is the a memorial in any other places.