A memorial in the Roman Rite of the Catholic Church is a lower-ranked feast day in honour of a saint, the dedication of a church, or a mystery of the religion. All feast days are ranked according to their importance and named either as “solemnities", or "feasts", or "memorials". Memorials are always supplanted by a coinciding solemnity, feast, Sunday, Ash Wednesday, Holy Week, or day of the Octave of Easter. Present rules Observance Celebrations of solemnities and feasts are distinguished from those of memorials by, for instance, recitation of the Gloria in excelsis in the Mass (an inclusion otherwise allowed only on Sundays) and the Te Deum in the Liturgy of the Hours. The observance of memorials is integrated into the celebration of the occurring weekday (the feria) according to the norms set forth in the General Instruction of the Roman Missal (GIRM) and the Liturgy of the Hours. The GIRM lays down that, for memorials of saints, "unless proper readings are given, the readings assigned for the weekday are normally used. In certain cases, particularised readings are provided, that is to say, readings which highlight some particular aspect of the spiritual life or activity of the Saint. The use of such readings is not to be insisted upon, unless a pastoral reason truly suggests it". The Collect proper to the memorial is used or, if this is lacking, one from an appropriate Common. As to the Prayer over the Offerings and the Prayer after Communion, unless these are proper, they may be taken either from the Common or from the weekday of the current time of the year. Celebrations of memorials occurring between 17 and 24 December and during Lent, which are then never obligatory, consist of replacing the collect of the day with that of the saint. The General Instruction of the Liturgy of the Hours gives the following indications on celebration of memorials occurring on ordinary days: In the Office of Readings and at Lauds and Vespers: a) All the psalms with their antiphons are taken from the current weekday, unless the memorial has proper antiphons and psalms. b) If the memorial has its own antiphon for the invitatory, hymn, short reading, Benedictus and Magnificat antiphons and intercessions, these are used. Otherwise these elements are taken either from the Common or from the Office of the current week and day. c) The concluding prayer is taken from