Catholics in England were forbidden to practice their faith openly during the years from 1558 to 1829. This song was developed to communicate their gift of faith in coded lyrics. The 12 days run from 25 December Christmas to 6 January (Epiphany). The True Love refers to God. The repetition of the melody signifies God's continual renewal of His gift.
A partridge is the symbol of Christ. The partridge will feign injury to protect nestlings who are defenseless, just as we are before Satan without Christ. A pear tree is the symbol of the salvation of humanity, just as the apple tree signifies human downfall.
Two turtle doves symbolize the Old Testament sacrifice offered by even the poorest of people in Israel (with which Christ was redeemed by His parents at His presentation in the Temple).
Three French hens, valued for their beauty and rarity, symbolize the gifts of the three Wise Men, as also the three theological virtues of Faith, Hope, and Charity.
Four calling birds represent the four major prophets and the four Evangelists, the former announcing His coming and the latter proclaiming His message.
Five golden rings represent first and foremost the five most precious Crucifixial Wounds of Christ (to which there had long been great devotion, and thus the reason for the change in the melody at this point), as also the perfect circle of faith: God's love for us, our love for God, and our love for each other. The number five refers as well to the five obligatory sacraments (Baptism, Penance, the Holy Eucharist, Confirmation, and Extreme Unction) as also the five books of the Bible which make up the Pentateuch, also known as the law, in the Old Testament.
Six geese a-laying represent the six days of creation.
Seven swans a-swimming are the seven Gifts of the Holy Ghost and the seven Works of Mercy (there are seven works of Corporal Mercy and seven of Spiritual Mercy).
Eight maids a-milking are the eight Beatitudes preached by Christ in the Sermon on the Mount, as well as the eight occasions during the year that were prescribed at that time for the reception of the Holy Eucharist.
Nine ladies dancing are the nine ranks of angel choirs, the Spirits who surround the Throne of God.
Ten lords a-leaping represent the Ten Commandments.
Eleven pipers playing are the eleven surviving Apostles proclaiming the Resurrection of Jesus.
Twelve drummers drumming are the twelve minor Prophets of the Old Testament and the twelve points of the Apostle's Creed. They symbolize also the Twelve Tribes of Israel, and the twelve Apostles (their number being restored after Pentecost), as also the twelve Fruits of the Holy Ghost, Who came down at Pentecost. Twelve is also the Scriptural number representing completeness and fairness.