One day in June 1195, around noon, something unusual took place near the city of London. A dark cloud appeared to give birth to a white orb of light, which dropped towards the Thames river, rising and falling in a spinning motion.

The observation – recorded by the Benedictine monk Gervase of Christ Church Cathedral Priory in Canterbury, England – is unlikely to be a first-hand account, and is otherwise light on detail. Nonetheless, it just might be the earliest convincing mention of a mysterious meteorological phenomenon in English history.

If we go by eyewitness accounts, ball lightning seems like a misnomer. While commonly seen during thunderstorms, they appear less like massive, explosive flashes and more like silent, grapefruit-sized, glowing spots that drift around for a handful of seconds before blinking out of existence.

There's no shortage of speculation over the physical nature of these bright spheres, from the more mundane explanation of blobs of plasma accumulating on insulated surfaces, to the more wild suggestions of refractive bubbles of trapped photons.

Just to add to the frustrations of those wishing to understand them, details on the appearance and behavior of these balls vary significantly. Some appear much larger than a handspan, for example, up to the size of a truck tire in one case.

Most are silent, disappearing with all the fervor of a popped soap bubble. Some explode violently. Few cause harm, though there are stories of damage and even injuries being sustained by making contact with ball lightning.

Being so rare and unpredictable, researchers rely heavily on anecdotes across different cultures and from throughout history to scratch together the necessary amounts of data to form hypotheses on what causes ball lightning in the first place.

With most reliable accounts taking place just in the past century or so, uncovering clear descriptions of ball lightning sightings in times gone by becomes all the more valuable. Old descriptions exist, but few are easy to distinguish from plain old flashes of lightning.

Two Durham University researchers, physicist Brian Tanner and historian Giles Gasper, recently published their findings of a relatively unambiguous recording which predates what had been the earliest account in England by around 450 years.

The monk's Chronicle was most likely written around the start of the 13th century, with translations being made over time and preserved in collections in the British Library and Cambridge.

One of these copies, a Latin text edited in 1879 by Bishop William Stubbs, was subsequently translated into the following English by Gasper.

"On the 7th of the ides of June [1195], around the sixth hour, a marvellous sign descended near London. For the densest and darkest cloud appeared in the air growing strongly with the sun shining brightly all around. In the middle of this, growing from an uncovered opening, like the opening of a mill, I know not what [was the] white colour [that] ran out. That, growing into a spherical shape under the black cloud, remained suspended between the Thames and the lodgings of the bishop of Norwich. From there a sort-of fiery globe threw itself down into the river; with a spinning motion it dropped time and again below the walls of the previously mentioned bishop's household."

The identity of the observer isn't clear, though it's unlikely to be the monk himself. By the year 1200, he was a seasoned chronicler of around 50 years of age based in Canterbury. Based on previous writings that include surprisingly accurate descriptions of solar eclipses, we can safely assume his reporting to be unembellished.

The description itself is also similar enough to many modern reports to be accepted as authentic and reliable.

"Gervase's description of a white substance coming out of the dark cloud, falling as a spinning fiery sphere and then having some horizontal motion is very similar to historic and contemporary descriptions of ball lightning," says Tanner.

As old as it is, the passage was written down a good 500 years after the current world record for earliest claimed report of ball lightning, written by the 6th century French historian Gregory of Tours in his book Historia Francorum.

In it he writes "a great ball of fire fell from the sky and moved a considerable distance through the air, shining so brightly that visibility was as clear as at high noon."

Interestingly, Gregory notes the event occurred just as the "bell had wrung for matins", which indicates it happened early in the morning. This makes it one of the more unusual examples of ball lightning, which accounts tend to describe as occurring later in the day. Later in the text the historian suggests the sighting was an omen for the death of the king's son.

Just how big "great" is, whether it moved laterally or vertically, or how bright it was, we can only guess. All we know is it was a fiery ball that appeared during rain, moved a distance, and then vanished behind a cloud.

With Gervase's clear description taking place around midday, of a ball descending from a dark cloud that was surrounded by clear sky, spinning, rising and falling, we have a few more data points that can clarify the circumstances under which these strange phenomena can appear.

This research was published in Weather.