A note on the Great Litany
The Great Litany (pgs 148-153) is an intercessory prayer including various petitions that are said or sung by the leader, with fixed responses by the congregation. It was used as early as the fifth century in Rome. It was led by a deacon, with the collects led by a bishop or priest. The Litany was the first English language rite prepared by Archbishop Thomas Cranmer. It was first published in 1544.
The Great Litany may be said or sung. The officiant and people may kneel or stand, or it may be done in procession. The Great Litany may be done before the Eucharist, or after the collects of Morning or Evening Prayer, or separately. Because of its penitential tone, it is especially appropriate during Lent. The Great Litany includes an invocation of the Trinity; a series of deprecations1 which seek deliverance from evil, spiritual harm, and natural calamities; a series of obsecrations 2 which plead the power of Christ’s Incarnation, life, death, and resurrection for deliverance; prayers of general intercession; the Agnus Dei; the Kyrie; the Lord’s Prayer; a versicle and response based on Ps 33:22; a concluding collect; and the grace (BCP, pp.148-154). The Supplication (BCP, p. 154) may be used at the conclusion of the Great Litany, taking the place of all that follows the Lord’s Prayer.
When the Great Litany precedes the eucharist, the Litany concludes with the Kyrie and the eucharist begins with the salutation and the collect of the day (BCP, p. 153). The Great Litany should not be preceded by a hymn, psalm, or anthem when it is used as an entrance rite at the eucharist. The Great Litany takes the place of the prayers of the people at the eucharist. The confession may also be omitted.
The Great Litany from https://www.episcopalchurch.org/library/glossary/great-litany
1 a prayer against something
2 A supplicatory prayer mentioning in its appeal things or events held to be sacred