At Easter in 1570 in the Church of St. Erasmus, the consecrated Host, according to the traditional rite at the time, was placed in a round silver container (pyx) and placed in a burse-like holder. This was later placed in a large, ceremonial silver chalice with its paten; the whole wrapped in an elegant silk cloth. It should be mentioned that at that time exposition of the Blessed Sacrament in a monstrance was not a widespread practice, even though the Council of Cologne (1452) specifically referred to the monstrance.
It was the custom for each civil confraternity to be present for an hour of adoration before the exposed Blessed Sacrament. It was at one of these hours of adoration which had the members of the Confraternity of Mercy (which predated both the Confraternity of Corpus Christi and of our Blessed Lady) vested in their black robes and kneeling in prayer. The most authentic document about this Eucharistic miracle was taken immediately by the chancery. This document is preserved in the archives of the Church of St. Erasmus.
The detailed deposition and account of the miraculous event is given by a Giacomo Meloni who was among the first witnesses. His testimony follows: "Raising my eyes towards the chalice, I saw a most brilliant star at the base of the chalice’s cup, and above the star, the Blessed Sacrament in the size of the Host used by the priest at Mass. The star was attached to the Blessed Sacrament (...). The vision ended when small children in adoration, similar to small angels, were seen around the Sacred Host...".