Some now aren’t so sure. Carbon dating is casting doubts on just how old this famous robe might be:

Friars from two churches of the Franciscan order founded by the saint asked a laboratory specializing in dating artwork to examine two simple brown tunics said to have been worn by the champion of the poor, as well as a mortuary cushion.

Francis who gave up the life of a playboy and soldier and all his worldly goods to dedicate himself to the poor and preach the way of peace, died in 1226. His hometown, Assisi, attracts millions of Christian pilgrims every year.

Artistic depictions of the saint show him dressed in a brown robe with a rope belt — the habit still worn by his order.

Four Franciscan churches have claimed to house relics. The tests showed that one, in the Basilica of Cortona in Tuscany, did date from his lifetime, as did an embroidered cushion said to have come from his deathbed.

A second robe from Florence’s Basilica of the Holy Cross did not match the dates, though the belt around it did.

“The tunic and cushion from Cortona were found compatible with the period in which Saint Francis lived but the one from Florence wasn’t,” said Pier Andrea Mando of the Nuclear Physics Laboratory in Florence, in a statement released on Wednesday.

The other two robes are kept in churches in Assisi and Arezzo belonging to a different branch of the order and were not included in the tests, which used accelerator mass spectrometry to measure the amount of carbon-14 present in samples of cloth.

Well, we all know the controversy surrounding carbon dating — and some of the same doubts and questions have already been raised about the Shroud of Turin.

I got to see that fabled robe for myself a few years ago, on a pilgrimmage to Assisi. It’s moving to behold, and to ponder. No less an authority than Sister Wendy Beckett has dissected it on one of her celebrated video tours of the art world. This is one of those enduring mysteries that may never be fully answered.