It can look idyllic, with its blankets of spring bluebells, white washed lighthouse and swooping colonies of seabirds.

But the tiny island of Flat Holm, three miles out from Lavernock Point and a familiar sight from the Cardiff coastline, holds stories which are anything but. Indeed, this rocky outcrop, just 500 metres in diameter, is steeped in tales of death, disease and starvation.

Read more:Living on Flat Holm island during lockdown by the only man who lives there

For instance, it's said that not only were the murderers of Thomas à Becket buried there but an invading army of warrior Danes was left to starve to death on its shores.

It was also once home to a cholera station where sick and infectious patients from all over Europe were sent to live out their last days.

In addition, Flat Holm provided plenty of firepower in the fight against Hitler's forces during WWII.

However, 1170 was the year when the then Archbishop of Canterbury was assassinated by a group of knights from the West Country who overheard - and took quite literally - King Henry II utter the now infamous words, "Will no one rid me of this turbulent priest?"

Henry and the Archbishop had been at loggerheads for many years, and his murder would send shockwaves throughout the medieval world.

One of the time-worn stories about what happened to his killers tells of how Sir William de Tracy and his counterparts were dug up and re-buried on the Welsh island, although there's little real evidence for this.

Flat Holm Island
Flatholm Island
Flatholm Island

Even earlier than that though, in the early 10th century, a band of marauding Vikings encamped on the island and turned it into a base of sorts - indeed, the word 'holm' derives from the old Norse for 'river island'.

However, the conditions on Flat Holm were so harsh and food so scarce that they almost starved to death there.

Legend has it that they'd been pillaging their way along the Welsh coast until they were finally dispatched by a Saxon army from Hereford and Gloucester.

Some of the Vikings would finally escape Flat Holm for Dyfed and from there they moved onto Ireland.

Then, in 1883, a makeshift hospital was authorised on the island to protect Cardiff from ship-borne cholera.

Wales' capital had already been hit hard by the disease by that point- overcrowded, with poorly ventilated housing and dirty drinking water, 383 people were killed when the epidemic swept the city's streets in 1849.

In July 1883, a steamship called Rishanglys left three seamen on the island who were believed to be suffering from cholera, one of whom subsequently died.

Nine years later, after a serious outbreak of cholera in Hamburg, Germany, five infected vessels were discovered and moored off Flat Holm.

According to the Cardiff Harbour Authority, patients were removed and taken to Flat Holm’s hospital.

Inside part of the hospital

In 1896 the Cardiff Corporation leased land for £50-a-year from Flat Holm's owner the Marquis of Bute, on which they'd eventually build a permanent sanatorium to be used by cholera patients.

However, in 1935 the Ministry of Health condemned the building and the island would become occupied by the military for a second time during WWII - the first having been between 1866 and 1903 following ultimately unfounded concerns France might invade the UK.

As Allied forces took on Nazi Germany between 1940 and 1944 the isolation hospital was converted for wartime service.

And remnants of the island's military history endure to this day, with the cholera hospital being restored as a visitor attraction.

To get the latest email updates from WalesOnline click here.