When the world’s most delicate historic sites need expert attention, it’s often the same group at the end of the line: the Compagnons du Devoir.

In 1984, when the Statue of Liberty got a new torch. In 1990, to fix the stately hurricane-damaged homes of Charleston, South Carolina. And now, with its roof in ashy tatters, Notre Dame du Paris.

The Compagnons are a secretive, UNESCO-protected band of artisans, with medieval origins. They are all but certain to be tasked with repairing this beloved national symbol. Based in France, they are among the best craftspeople in the world, trained over years in a lengthy process steeped in an almost-masonic level of mystery, ritual, and devotion to their trades. As I wrote for Atlas Obscura:

The name “compagnon” translates to “companion,” relating to the brotherhood between members and the shared identity of a movement that, today, encompasses around 12,000 permanent, active members. Professions usually fall into one of five “groups,” depending on their principal material: stone; wood; metal; leather and textiles; and food. Within these groups are bakers, clog-makers, carpenters, masons, glaziers, and many more. In the past century, new trades have been added while old ones have fallen away. As young people, they live in boarding houses together in towns across France, where they spend their days learning and training to become the country’s greatest tradespeople. After six months in one place, each tradesman will pack up and move on to another French town, and a new hostel, to learn more skills under a new master.

They now have a tremendous challenge ahead: repairing one of the world’s best-loved medieval cathedrals, and ideally within five years. As Notre Dame burned, Compagnons spokesman Patrice Bernard told Le Télégramme, his phone scarcely stopped ringing. “I received huge numbers of texts and emails from Compagnons asking what they could do to help.” The cathedral, built and rebuilt over centuries by their professional ancestors, is hugely important to the present-day Compagnons—now, it will be up to them to restore it to its former glory.

A lingering concern is whether they have enough capacity to fix Notre Dame while continuing their care of France’s other architectural treasures. According to a Le Monde report, Notre Dame will need 100 stonecutters, 150 carpenters, and 200 roofers to help with repairs from September: Though there are currently enough in the Compagnons’ ranks to fill that demand, they may have to move them off other projects.

Finding and retaining young people to join their ranks is an increasingly heavy task. “These manual professions are very undervalued, and attract few people,” the Compagnons’ secretary-general, Jean-Claude Bellanger, told reporters. The group has tried advertisements, public information stalls, and even a Facebook account to encourage young people to train to become Compagnons.

With Notre Dame’s reparation in the headlines, the Compagnons now have a rare opportunity to be national heroes. Whether this moment of glory can set off a new wave of interest in beginning the long journey toward becoming a master craftsperson is more unsure.