The Angelus Domini, shortened to "the Angelus," is the ringing of the church bell -- in three groups of three chimes with a pause in between each group, followed by 9 consecutive strokes -- at 6AM, Noon, and 6PM roughly, and its associated prayers, which spring from the monastic practice of praying the tres orationes at Matins, Prime and Compline. While the monastics said their prayers at the sound of the Angelus Bell, the faithful would stop what they were doing and say 3 Hail Marys in honor of the Incarnation. Later, since at least A.D. 1612, verses were added to these Hail Marys such that we get the form of the Angelus we have today (see below). During Paschaltide (the Easter Season), the humbling Angelus prayer below is replaced with the more celebratory, joyous Regina Coeli prayer at the direction of Pope Benedict XIV in 1742.
Some of the earliest bells used for this purpose, dating to the 13th and 14th centuries, still survive and are engraved with inscriptions attesting to their purpose. Some of these inscriptions are (from the Catholic Encyclopedia):
Ave Maria, gratia plena, Dominus tecum (Hail Mary, full of grace, the Lord is with thee)
Dulcis instar mellis campana vocor Gabrielis (I am sweet as honey, and am called Gabriel's bell)
Ecce Gabrielis sonat hæc campana fidelis (Behold this bell of faithful Gabriel sounds)
Missi de coelis nomen habeo Gabrielis (I bear the name of Gabriel sent from heaven)
Missus vero pie Gabriel fert læta Mariæ (Gabriel the messenger bears joyous tidings to holy Mary)
O Rex Gloriæ Veni Cum Pace (O King of Glory, Come with Peace)
