Liturgical memory is the term of the Roman Rite) is used to indicate those celebrations of the sancoral that have less liturgical importance than feasts and solemnities. It can be mandatory, if to be celebrated every year unless prevented by a Sunday or by a celebration of higher rank, or optional (ad libitum), if the decision whether to officiate or not is left to the celebrants.
Most celebrations of the saints have the degree of memory. The memorial does not foresee either the singing of the Gloria or the Creed, which are exclusive of feasts and solemnities the first, the second of solemnities.
Memories are celebrated only if a celebration of greater importance does not fall on the same day: for this purpose, the Missal and the books of the Liturgy of the Hours show at the beginning a table in which the relative importance of the various celebrations of the liturgical year is determined. and their mutual precedence.
In particular, the memories that fall in Lent are celebrated in an even lesser tone, in order to avoid depriving the strength of Lent itself, and are called commemorations: in this case the saint is mentioned exclusively in the collection.
Memories in the General Roman Calendar
The following liturgical celebrations have a compulsory degree of memory. To these, at the local level, are added the memories proper to dioceses and congregations; in these contexts, moreover, some recurrences can assume the degree of feast or solemnity, or be celebrated on different dates (generally the following day) in case of permanent occurrence with local recurrences of a higher degree or of a previous institution.
The Eucharistic celebration in the memories
On days in which a memorial falls, the liturgical prayers proper to the saint of whom the memorial is made are used in the Eucharistic celebration.
The liturgy of the word is that of the feria, unless explicit mention of the saint is made in the first reading or in the Gospel: in this case the readings reported in the proper of the saints or in the respective municipality are used.
The liturgy of the hours in the memoirs
In the liturgy of the hours, the second reading of the Office of Readings must necessarily be taken from the santorale. The other parts only when explicitly indicated.
In particular, the first reading of the Office of Readings is never changed: the rubrics of the breviary require that the feria be read faithfully, unless a feast or solemnity is being celebrated.
In the morning Lauds and Vespers, the psalms of the feria are recited in most of the memoirs. Some memoirs are an exception. The short reading with its responsory, the antiphon to the Gospel canticle, the invocations and intercessions can be taken from the feria or from the commune, unless the santorale indicates proper texts.
If a memory occurs during the time of Lent, it can be celebrated as a "commemoration" in the following way: first the entire office planned for the feria of Lent is celebrated, then some parts of the saint being celebrated are added. In the office of readings, after the second reading with its responsory, the proper hagiographic reading is added with the responsory sound and the saint's prayer; in the morning praises and in the vespers, after the concluding prayer, the antiphon and the proper prayer are added.
A particular optional memory in the liturgy of the hours is that of Santa Maria in Sabato.
Liturgical year in the Catholic Church
List of Catholic liturgical books
Liturgy of the hours