Saint Patrick's Breastplate

Saint Patrick's Breastplate, also known as The Deer's Cry or The Lorica of Saint Patrick or Saint Patrick's Hymn is a lorica whose original Old Irish lyrics were traditionally attributed to Saint Patrick during his Irish ministry in the 5th century. In 1889 it was adapted into the hymn I Bind Unto Myself Today. A number of other adaptions have been made.

The prayer is part of the Liber Hymnorum, a collection of hymns found in two manuscripts kept in Dublin and published in 1903 in the Thesaurus Paleohibernicus. The document gives this account of how Patrick used this prayer:

Patrick sang this when an ambush was laid against his coming by Loegaire, that he might not go to Tara to sow the faith. And then it appeared before those lying in ambush that they (Patrick and his monks) were wild deer with a fawn following them.

The description concludes "fáeth fiada a hainm", which the Thesaurus Paleohibernicus translates as "Its name is 'Deer’s Cry'. However, the phrase 'fáeth fiada' is used elsewhere in Irish mythology to mean a mist of concealment.

If the description above is accurate then the prayer would date from the 5th century – the time of Saint Patrick. However, it has been dated as from the 8th century by modern experts. Although Christian in content, it shows pre-Christian influence in that it calls for Christ's protection using the form of a pagan invocation of the gods or lorica (shield or breastplate). Because of this it is also known as the "Lorica of St. Patrick" or as "St. Patrick's Breastplate". On the other hand, this may be a Scripture reference, specifically: Ephesians 6:10–17 ("God's shield to protect me ... from snares of devils").

Each verse of the prayer begins "Atomruig indiu" "I arise today" or "I bind unto myself today" and this phrase is repeated at the beginning of most of the verses. This is followed by a list of sources of strength that the prayer calls on for support.

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