Discover the Eucharistic Miracle of Siena: the Sacred Hosts Incorrupt for Three Centuries

In the Basilica of San Francesco in Siena a silent, verifiable miracle is renewed every day: 223 Hosts consecrated in 1730 remain whole, fragrant and incorrupt after almost three centuries, defying every natural law governing the decay of organic matter. It is the most studied “permanent miracle” in Italy, before which saints, scientists and popes have bowed.

The Theft on the Eve of the Assumption

On the night between 14 and 15 August 1730, while the people of Siena were attending the celebrations for the eve of the Assumption, unknown thieves broke into the church of San Francesco and stole the golden ciborium containing 351 consecrated Hosts. The sacrilegious theft plunged the city into dismay: the Palio itself was suspended as a sign of mourning and reparation.

Three days later, on 17 August, the Hosts were found in the alms box of the sanctuary of Santa Maria in Provenzano, covered in dust but intact. Cleaned and counted, they were carried back in solemn procession to San Francesco. They were never consumed: it was expected that they would deteriorate naturally. That never happened.

A Continuing Prodigy: the Scientific Examinations

Over the centuries the Sacred Hosts have been repeatedly examined: the official inspections — including that of 1914 ordered by Saint Pius X with microscopic and chemical analyses — have always found the Hosts whole, their starch perfectly preserved, with no trace of corruption or preserving agents. Unleavened bread, which naturally decomposes within a few years, has remained intact since 1730. Saint John Paul II, visiting Siena in 1980, exclaimed: “It is the Presence!”.

The Basilica of San Francesco

The great Gothic church that guards the Hosts dominates the city from the hill of the same name. Inside, the Chapel of the Sacrament with the Sacred Hosts is a place of continuous adoration; on the 17th of every month the Sienese community gathers in prayer before the prodigy.

Historical Clues and “Adventurous” Research:

• The documented inspections: from 1730 to the present there have been numerous official examinations: reconstructing the complete series is a journey between science and faith unique in the world.
• The suspended Palio: the chronicles of 1730 describe an entire city in mourning over the sacrilege: a vivid fresco of Sienese history.
• The comparison with control hosts: in the modern inspections, unconsecrated hosts were kept as “controls”: they decomposed normally, while the Sacred Hosts remained intact.

Useful Information for Pilgrims

• Address: Piazza San Francesco, Siena (SI), Italy
• Opening Hours: check the website of the Basilica of San Francesco or the Archdiocese of Siena for adoration and celebration times.
• Getting There: the basilica stands in Siena’s historic centre, a ten-minute walk from Piazza del Campo.

Historical source: the international exhibition “The Eucharistic Miracles of the World” created by Carlo Acutis (miracolieucaristici.org).