The lyrics of the carol are by English hymnwriter John Mason Neale, Warden of Sackville College, East Grinstead, Sussex (18181866). He may have written his carol some time earlier, since he carried on the legend of St. Wenceslas on which it is based in his Deeds of Faith (1849). Neale was known for his devotion to High Church traditions. According to older Czech sources, Neale's lyrics are a translation of a poem by Czech poet Václav Alois Svoboda, written in Czech, German and Latin.
The tune is that of "Tempus Adest Floridum" ("It is time for flowering"), a 13th-century spring carol, first published in the Swedish/Finnish Piae Cantiones, 1582.
In or around 1853, G. J. R. Gordon, her majesty's envoy and minister in Stockholm, gave a rare copy of the 1582 edition of Piae Cantiones to Reverend Neale and to Reverend Thomas Helmore (Vice-Principal of St. Mark's College, Chelsea). The book was entirely unknown in England at that time.
Neale translated some of the carols and hymns, and in 1853, he and Helmore published twelve carols in Carols for Christmas-tide (with music from Piae Cantiones). In 1854, they published a dozen more in Carols for Easter-tide. The inspirational copy of Piae Cantiones is now said to be in the British Museum.
The lyrics of Neale's carol bear no relationship to the words of "Tempus Adest Floridum". A text beginning substantially the same as the 1582 "Piae" version is also found in Carmina Burana as CB 142, where it is substantially more carnal.