This song has one of the most mysterious origin stories, being variously attributed to British hymnist John Francis Wade, British composer John Reading, or King John IV of Portugal. The oldest known original manuscript is in the Stonyhurst College in Lancashire, dating back to 1751. It is thought that the original Latin version, Adeste Fideles, may have been written by John Francis Wade shortly before fleeing England in 1745 as part of the Jacobite rebellion, a political movement during the War of Austrian Succession to take back the throne for James Francis Edward Stuart.

The Mormon Tabernacle Choir performing O Come, All Ye Faithful.

Some historians have speculated that the song might have been used as a cipher, using the lyrics as a secret political code, as Bethlehem was often used as a code word for England. The song’s reputation as “the Portuguese hymn” adds another level of mystery. It may be as simple an answer that it was a favorite tune at the Portuguese Embassy, although some believe that King John of Portugal, commonly known as “The Music King,” wrote the song in the 1640s. Today, O Come, All Ye Faithful is performed as the penultimate hymn at the carol festival at the Choir of King’s College, the world’s most renowned choral performances.

Lyrics

O Come All Ye Faithful
Joyful and triumphant,
O come ye, O come ye to Bethlehem.
Come and behold Him,
Born the King of Angels;
O come, let us adore Him,
O come, let us adore Him,
O come, let us adore Him,
Christ the Lord.

O Sing, choirs of angels,
Sing in exultation,
Sing all that hear in heaven God's holy word.
Give to our Father glory in the Highest;
O come, let us adore Him,
O come, let us adore Him,
O come, let us adore Him,
Christ the Lord.

All Hail! Lord, we greet Thee,
Born this happy morning,
O Jesus! for evermore be Thy name adored.
Word of the Father, now in flesh appearing;
O come, let us adore Him,
O come, let us adore Him,
O come, let us adore Him,
Christ the Lord.