In Christian worship, Marian litany is a form of prayer to Mary, mother of Jesus used in church services and processions, and consisting of a number of petitions.
Marian litanies are numerous in the Eastern church and may cover a multitude of themes, some dogmatic, others of moral and patriotic character.
In the liturgy of the Western Church the word litany is derived from the Latin litania, meaning prayer of invocation or intercession.
[1] The first Marian litanies must have been composed to foster private devotion, as it is not at all probable that they were written for use in public, by reason of their drawn-out and heavy style.
[2] The earliest known genuine text of a Marian litany is in a 12th-century codex in the Mainz Library, with the title Letania de domina nostra Dei genitrice virgine Maria: oratio valde bona.
And in order that this repetition might not prove monotonous in the Middle Ages recourse was had to an expedient since then universally used, not only in private devotions but even in liturgical prayer, that of amplifying by means of what are called tropes.
It was an easy matter to improvise between the "Sancta Maria" and the "Ora pro nobis", repeated over and over, a series of tropes consisting of different praises, with an occasional added petition, imitated however broadly from the litanies of the saints.
The first place is given to praises bestowed on the name of "Mater"; then come those expressing the Blessed Virgin's tender love for mankind; then the titles given her in the creeds; then those beginning with "Regina", which are identical with those we now have in the Litany of Loreto.
It is probable that the Loreto text became customary in the Holy House towards the close of the 15th century, at a time when in other places similar litanies were being adapted for public use to obtain deliverance from some calamity.