Knock, August 21, 1879

At about 7:30 p.m. on august 21, 1879, Mary Beirne and the housekeeper for the parish priest witnessed an apparition of the Blessed Virgin near the gable of the church in the small town of Knock in County Mayo. They saw three figures: the figure of the Blessed Virgin was in the center; to Her right was St. Joseph; to Her left a Bishop, identified by Mary as St. John the Apostle, vested for Mass, holding a book in his left hand, his right hand raised as in blessing. To the left of St. John was a full-sized adorned altar on which stood a lamb, turned toward the Virgin; behind the lamb was a large cross.

The vision lasted for two hours and was witnessed by at least 15 persons, all of whom gave sworn testimony to what they had seen. Three similar visions were reported on January 6, February 10 and 12, 1880.