Epiphany or Theophany, which traditionally falls on January 6, is a Christian feast day that celebrates the revelation of God the Son as a human being in Jesus Christ. Western Christians commemorate principally the visit of the Magi to the Baby Jesus, and thus Jesus' physical manifestation to the Gentiles. Eastern Christians commemorate the baptism of Jesus in the Jordan River, seen as his manifestation to the world as the Son of God. Eastern Churches following the Julian Calendar observe the Theophany feast on what for most countries is January 19 because of the 13-day difference today between that calendar and the generally used Gregorian calendar. Since 1970, the rule for the Roman Rite of the Catholic Church is: "The Epiphany of the Lord is celebrated on 6 January, unless, where it is not observed as a holy day of obligation, it has been assigned to the Sunday occurring between 2 and 8 January." In the Church of England, the eve of the feast used to be celebrated as Twelfth Night. The Monday after Epiphany is known as Plough Monday.