LOW SUNDAY
Low Sunday is also known as the Octave of Easter (which can also refer to the entire eight days from Easter Sunday to Low Sunday), Divine Mercy Sunday (Roman Catholics), St. Thomas Sunday (Eastern Christians), Antipascha, Thomas Sunday, Renewal Sunday (Eastern Orthodox, Coptic Orthodox Christians), Quasimodo Sunday, Quasimodogeniti, the Second Sunday of Easter, or the Eighth day of Easter. It is the Day after the legitimate Easter Saturday (After Easter Sunday) In Santiago, Chile, Quasimodo Sunday is celebrated with the Cuasimodo Feast and parade.
DIVINE MERCY SUNDAY
In Roman Catholicism, Low Sunday is known as Divine Mercy Sunday. It comemorates an entry in the diary of St. Faustina (Maria Faustina Kowalska) stating that anyone who participates in the Mass and receives the sacraments of Confession and the Eucharist on this day is assured by Jesus of full remission of their sins and punishments. The Day was also designated as Divine Mercy Sunday by Pope John Paul II on April 30, 2000.
SAINT THOMAS SUNDAY
In Eastern Christianity, the day is referred to as St. Thomas Sunday. It comemorates the event of Thomas the Apostle comes to coming to believe in the Resurrection of Jesus after being told by the resurrected Christ to place his finger in the nail marks and his hand in His side on the eighth day after the Resurrection.
ANTIPASCHA
In the Eastern Orthodox Church and the Coptic Orthodox Church the day is known as Antipascha, Thomas Sunday, Renewal Sunday, or the Eighth Day of Pascha. It comemorates the the re-dedication of the Resurrection of Christ and the event of the Holy Apostle Thomas' touching the wounds of Christ.