WHEN the great 16th Century prophet Nostradamus stared into the future, he described the fate of the final pope with eerie detail. And the first sign will soon be in our skies.

The 266th pope now sits on the Throne of St Peter. According to the pen of several prophets, he will be the last.

One prophet, a Saint of the Catholic Church, counted down the popes until the end of the world. After Pope Francis there are no more on that list.

Nostradamus himself foresaw the end of a pope and the Church itself at a time when a great comet was to fill our skies. Comet Ison, said to be one of the brightest for centuries, will pass by later this year.

Their ancient words have set speculation ablaze on internet forums and in social media debates.

Anything mentioning Nostradamus is bound to fire up imaginations.

From his smoke-filled room in 16th century Renaissance France, the prophet wrote one of his characteristically tantalising four-line prophetic "quatrains":

Quatrain II.46

"The great star for seven days shall burn

So nakedly clear like two suns appearing

The large dog all night howling

While the great Pontiff shall change his territory."

Astronomers have announced that Comet Ison, which will pass later this year, could end up being brighter than the moon - if it survives its encounter with the sun.

This has been seized upon as evidence that Nostradamus's words are about to come to pass.

Another of Nostradamus's writings has also been associated with the end of the Catholic Church:

Quatrain VI.6:

There will appear towards the North

Not far from Cancer the bearded star:

Susa, Siena, Boeotia, Eretria,

The great one of Rome will die, the night over.

Again a portentous comet is mentioned in association with a fateful event involving "the great one of Rome", a phrase he repeatedly used to refer to the Catholic Church.

As with all of Nostradamus' prophecies, these quatrains have been applied to various events over the centuries - most recently Pope John Paul II.

However, in this case, Nostradamus was not the only one to foretell the fate of the Catholic Church's final leader.

It is the writings of Saint Malachy, an archbishop of the 1100s, which definitively states this will be the pope of the end times.

A Benedictine monk claimed to have discovered in 1595 a collection of the Saint's papers where he had purportedly secretly written down 112 brief but vague prophecies. Each is associated with the reign of an individual pope.

The last phrase applies to Pope Francis:

Verse 112:

"In the final persecution of the Holy Roman Church, there will sit Peter the Roman, who will pasture his sheep in many tribulations, and when these things are finished, the city of seven hills will be destroyed, and the dreadful judge will judge his people. The End."

Such vague words are widely open to interpretation and will no doubt continue to generate speculation - even if another pope is elected.

And if Nostradamus and Saint Malachy are proven wrong, one can always fall back on prophecies from the likes of Sir Isaac Newton who predicts - based on his biblical calculations - that the world will end in 2060.