AD LIBITUM

AD LIBITUM. – This expression has several uses in liturgy. With regard to the “Rubrics,” it refers to the free use of certain “Collects” (v.). Musically, it concerns individual or collective recitative chants: individual, such as certain tones for Prayers, Epistles, Gospels, and Lessons; collective, such as various common tones of the Ordinary of the Mass, like Kyrie, Gloria, Sanctus, Agnus Dei, and also the Credo. In antiquity, the choice of the alleluia “Sicut volueris” was also synonymous with *a. l.* In Ambrosian chant, on certain days there are some longer “melismata” or “iubilus” to be used *a. l.* in the case of greater solemnity. In the interpretation of certain neumes, such as “stroficus,” *a. l.* may also be employed for the greater convenience of the choir. Guido d’Arezzo considered certain neumes to be *a. l.*, though he affirmed that in practice it was better to perform them.