On March 12, 1345, a few days before Easter, Ysbrand Dommer, thinking he was near the end of his life, sent for the parish priest of the church of Oude Kerk so he could receive the Last Rites. Shortly after receiving Holy Communion, he vomited everything into a small basin whose contents were then thrown into the flames of the fireplace. The next day Ysbrand was completely restored to health.
One of the maids taking care of him approached the fireplace to poke the fire and noticed a strange light centered on the Host that was intact. The woman began to scream and everyone within earshot ran to witness the miracle. Ysbrand recovered the Host and wrapped the Holy Eucharist in a linen cloth that was placed in a case and immediately carried the Blessed Sacrament to the parish priest.
But the miracle continued: three times the priest had to return to Ysbrand’s house to recover the Host that miraculously re-appeared there. It was then decided to turn Ysbrand Dommer’s house into a chapel. On Easter Sunday, everyone who had witnessed the miracle, and the mayor of Amstel, compiled a report of the events. The report was delivered to the Bishop of Utrech, Jan van Arkel, who authorized devotion to the miracle.