It's popularly called "Twelfth Day," which reminds us that it is the 12th day from Christmas - and the conclusion of the Christmas season and festivities.
The season of Epiphany begins with this feast, on which the Wise Men's visitation of the new born Christ is recounted in the day's mass propers, specifically in the gospel reading.
This year there will be SIX Sundays in the season of Epiphany, and the Sunday mass propers begin with Christ's appearances in the Jerusalem temple (Epiphany 1) when he was but 12 years old, His baptism in the Jordan river by John the Baptist (Epiphany 2), and his first miracle, wrought at a wedding in Cana of Galilee (Epiphany 3).
Assuredly, then, this is a good season to ponder how we, as modern followers of Christ, manifest Jesus in our life, by both what we say (or don't say) and what we do (or don't do).
The picture - an oil painting - which accompanies this article is entitled "The Adoration of the Magi," and was created by Jheronimus Bosch (early 16th Century).