According to physicists at the Italian Institute for Nuclear physics, the tunic below is claimed to have belonged to St. Francis of Assisi. Radiocarbon evidence suggests that the date of this artifact matches up to St. Francis' lifetime and lived devotion to God as a Franciscan monk.
St. Francis was a spiritual leader and founder of the Franciscan order in a time where living out a fulfilling spiritual journey was sought after. The Franciscans expressed their piety and devotion to God by living as mendicants, or beggars: living on the streets, begging for food, and dressing simply in their recognizable brown, gruff tunics. They believed living their lives out in poverty allowed them to ignore worldly objects and sacrifice their lives to God. This tunic represents one of the many new ways Medieval people found to express themselves religiously.
Now do I think this tunic belonged to THE St. Francis himself? No. Well, I don't know... Possibly? The chance is very, very, very slim. Extremely slim. But the authenticity of the artifact itself cannot be doubted thanks to science. Imagine St. Francis passionately preaching to the streets of Italy: his feet bare, raw, and caked in dirt, his tunic shredded, thin, and completely unsuited for the elements, but his face enlightened. He is completely fulfilled.
Sources
Bennett, Judith. "New Paths to God." Medieval Europe: A Short History. New York: McGraw Hill, 2011. 190-199. Print.