In 1411 at Ludbreg, in the chapel of the Count Batthyany’s castle, a priest was celebrating Mass. During the consecration of the wine, the priest doubted the truth of transubstantiation, and the wine in the chalice turned into Blood. Not knowing what to do, the priest embedded this relic in the wall behind the main altar. The workman who did the job was sworn to silence. The priest also kept it secret and revealed it only at the time of his death.
After the priest’s revelation, news quickly spread and people started coming on pilgrimage to Ludbreg. The Holy See later had the relic of the miracle brought to Rome, where it remained for several years. The people of Ludbreg and the surrounding area, however, continued to make pilgrimages to the castle chapel.
In the early 1500s, during the pontificate of Pope Julius II, a commission was convened in Ludbreg to investigate the facts connected with the Eucharistic miracle. Many people testified that they had received marvelous cures while praying in the relic’s presence.
On April 14, 1513, Pope Leo X published a Bull permitting veneration of the holy relic which he himself had carried in procession several times through the streets of Rome. The relic was later returned to Croatia. In the 18th century, northern Croatia was ravaged by the plague. The people turned to God to call upon His help, and the Croatian Parliament did the same. During the session held on December 15, 1739 in the city of Varazdin, they vowed to build a chapel at Ludbreg in honor of the miracle if the plague ended. The plague was averted, but the promised vow was only fulfilled in 1994, when democracy was restored in Croatia.
In 2005 in the votive chapel, the artist Marijan Jakubin painted a large fresco of the Last Supper in which Croatian saints and blesseds were drawn in place of the Apostles. St. John was replaced with Blessed Ivan Merz, who was included among the 18 most important Eucharistic saints in the Church’s history during the Synod of Bishops held in Rome in 2005. In the painting, Christ is holding in His hand a monstrance containing the relic of the Eucharistic miracle.