This is a video about Florence and the Santa Croce church.
From Italian news agency ANSA:
St Francis relic unmasked
Santa Croce tunic not old enough, researchers say
Rome, September 5 – Italian scientists have used new technology to unmask a relic of St Francis of Assisi as a fake.
Researchers from Florence’s Nuclear Technology for the Cultural Heritage (LABEC) lab trained a beam of low-energy particles across carbon-14 atoms taken from a tunic venerated in one of Florence’s most famous churches, Santa Croce.
The carbon-14 dated the fabric to the end of the 13th century, more than 70 years after the saint’s death.