For many devout Catholics, the timing of Tuesday’s fire at Paris’ Notre Dame Cathedral could not have been worse.

The 856-year-old gothic structure is home to several ancient relics believed to have been connected to Jesus Christ’s final moments on Earth.

On Tuesday (AEST) – just days before Easter – flames ripped through the cathedral’s roof, casting fears over the safety of sacred objects stored inside, including a piece of the Jesus’s cross, a nail and the Holy Crown of Thorns.

The Crown of Thorns is a braided circle of canes that was purportedly placed on the head of Jesus Christ before he was crucified by the Romans.

Originally from Jerusalem, the cherished relic is stored in a gold and glass shrine and is brought out only on Fridays during Lent and on Good Friday. This year, that is this coming Friday.

There had been early fears that the fire that ripped through most of the cathedral’s roof and toppled its famous spire had also destroyed the Crown of Thorns.

But mourners breathed a sigh of relief after Paris Mayor Anne Hidalgo said in a tweet that major sacred items, including the Crown, had been rescued.

“Thanks to the Paris Fire Brigade, the police and the municipal agents, the Crown of Thorns, the Tunic of Saint Louis and several other major works are now in a safe place,” Mayor Hidalgo tweeted.

Merci aux @PompiersParis, aux policiers et aux agents municipaux qui ont réalisé ce soir une formidable chaîne humaine pour sauver les œuvres de #NotreDame. La couronne d'épines, la tunique de Saint Louis et plusieurs autres œuvres majeures sont à présent en lieu sûr. pic.twitter.com/cbrGWCbL2N

— Anne Hidalgo (@Anne_Hidalgo) April 15, 2019

Chaplain of the Paris Firefighters Father Fournier said he braved the flames and went inside the burning cathedral to save the Blessed Sacrament and Crown of Thorns.

The Tunic of Saint Louis, another prized French relic, dating back to the 13th century, has also been recovered.

What else makes the Notre Dame so special?

In addition to housing some of the world’s most sacred religious relics, the Notre Dame Cathedral is also famous for its three rose-patterned stained-glass windows.

The windows date back to the 13th century, with the first finished about 1225. It is unlikely that any has survived the fire.

Notre Dame’s old stones will hold up, but I’m most worried about the rose windows. Here‘s the one at the southern end of the transept.

It dates from the year 1260. It’s twin on the northern end is even older, from 1250. pic.twitter.com/m43exXH0Sl

— Madeline Marsanne (@MadelineOnMars) April 15, 2019

Most of the cathedral’s detailed roof, nicknamed ‘The Forest’ due to its fine lattice of woodwork, has been destroyed.

A firefighter official said while the structure of the cathedral had been saved from “total destruction”, there is still a chance that parts of it could cave in due to the extent of the damage.

Other famous features feared damaged include mythical creatures known as gargoyles that sit on top of the cathedral and watch out over Paris.

The cathedral is also home to 10 ancient bells, the largest weighing more than 23 tonnes. It was installed in 1685.

Each bell has the name of a saint to replicate the original bells that were melted for cannon balls during the French Revolution.

The cathedral’s two bell towers are believed to have been saved.

Last week, 16 green copper statues representing the 12 apostles and four evangelists were removed from the cathedral for the first time in more than 100 years as part of its renovations.

The copper statues are normally located on the outside of the cathedral and watch over Paris from the structure’s highest point at 315 feet.

They were lowered by a crane and loaded into a truck for restoration just days before the cathedral caught fire on Tuesday.

No lives were lost in the fire, but one firefighter is believed to have been injured trying desperately to salvage the art and priceless artefacts inside.