Mysterium Fidei Museum

Museum in Valletta

CC BY-SA 4.0 / Simon Burchell

Hidden beneath St. Catherine's Monastery in the heart of Valletta, Mysterium Fidei is one of Malta's most intriguing and atmospheric museums — a subterranean world that had been closed to the public for over 400 years. Only recently opened, this underground complex and secret garden reveal the private, secluded lives of the cloistered nuns of the Second Order of Saint Augustine. Established in 1575, the monastery was originally founded to provide shelter and support for orphaned girls. The site, known then as Casa Vanilla, was donated by Marquis Giovanni Vasco Oliviero and his wife Katerina as an act of gratitude to God for curing their son of the plague. The couple not only gifted their home but also financed the construction of the cloister, added an additional floor, and donated their possessions to ensure the monastery's future.

The stones used to build St. Catherine's Monastery were quarried directly from beneath it, creating a network of underground tunnels, chambers, and living quarters that now form the Mysterium Fidei Museum. Visitors can explore the nuns' former world — from their simple bedrooms and laundry area to sewing rooms, kitchens, and prayer spaces. One section, known as the control rooms, offers insight into how the nuns once supervised and “reformed” young women who were deemed morally wayward by the standards of the time. The exhibition is both haunting and deeply human, revealing the nuns' austere yet purposeful way of life. During World War II, one of the underground rooms even served as an air-raid shelter, protecting the small community from the bombing raids that struck Valletta.

The museum also includes a hidden garden, a serene refuge that the nuns cultivated in secret. This tranquil space is home to herbs, fruit trees, three freshwater wells, and a few long-term residents — including chickens, rabbits, and a shy cat. Nearby lies the burial chamber, where the nuns were interred after death, honoring their vow never to leave the monastery, even in eternity. Candles were once placed beside each nun's deathbed as part of a solemn final procession. In the 1970s, new burial laws disrupted this centuries-old custom, forcing burials elsewhere, but an exemption later allowed the tradition to continue within the monastery walls. The preservation of this ritual gives visitors a rare and moving glimpse into the nuns' enduring faith and devotion.

Visiting Mysterium Fidei feels like stepping back through time — into a world of silence, prayer, and mystery. The site's combination of sacred architecture, hidden history, and human stories makes it one of Valletta's most captivating attractions.

The Mysterium Fidei Museum appears in our Complete Guide to Visiting Valletta!

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