Sub tuum praesidium

Beneath Thy Protection (Greek: Ὑπὸ τὴν σὴν εὐσπλαγχνίαν; Latin: Sub tuum præsidium) is the oldest preserved extant hymn to the Blessed Virgin Mary as Theotokos. The hymn is well known in many Roman Catholic, Eastern Orthodox and Oriental Orthodox countries, and is often a favourite song used along with Salve Regina.

The earliest text of this hymn was found in a Coptic Orthodox Christmas liturgy. The papyrus records the hymn in Greek, dated by scholar C.H. Roberts to the fourth Century, while his colleague Edgar Lobel favored a date ranging from AD 250-280. This divergence in dates is explained by Roberts' doubt that the term "Theotokos" was already in use by the third Century. We find it, however, in the writings of third Century theologians Origen and Pope Dionysius of Alexandria.

The hymn is used in the Coptic liturgy to this day, as well as in the Armenian, Byzantine, Ambrosian, and Roman Rite liturgies. It was part of Sulpician custom that all classes ended with a recitation of this prayer. Besides the Greek text, ancient versions can be found in Coptic, Syriac, Armenian and Latin.

Henri de Villiers finds in the term "blessed" a reference to the salutation by Elizabeth in Luke 1:42. "Praesidium" is translated as "an assistance given in time of war by fresh troops in a strong manner."

The former medieval and post-medieval practice in several dioceses, especially in France, was to use the Sub tuum as the final antiphon at Compline instead of the Salve Regina and in the Rite of Braga where it is sung at the end of Mass.

...
Wikipedia