King John infamously lost the Crown Jewels while trying to cross The Wash estuary in 1216, and a scientist has now discovered that the maligned monarch’s treasure was seized by the sea as a result of a freakishly large and powerful tide. 

Analysis of historical astronomy records revealed that the king’s convoy and riches fell victim to a double whammy: the alignment of the Sun and Moon in a new moon, as well as the Moon being at its closest to Earth, which created a powerful 22ft-high wave.

John was King of England from 1199 to 1216, and history remembers him as a poor king who pales in comparison to Henry II, his father, and Richard the Lionheart, his brother.

The monarch was known for his greed, which earned him the moniker “Bad King John”, and he has been immortalised in folklore as a main villain in the Robin Hood tales. 

On Oct 12 1216, a week before he died of dysentery, John tried to avoid enemy forces by crossing The Wash from King’s Lynn to Swineshead Abbey in Lincolnshire as the country feuded in the wake of the Magna Carta signing a year earlier. 

However, the king’s convoy was unexpectedly submerged by water after powerful waves destroyed and sank wagons carrying food, valuables and, purportedly, the Crown Jewels. 

Prof Donald Olson, an astronomer from Texas State University, discovered that the king’s misfortune was not because of poor planning or route choice, but a freakishly large wave called a “tidal bore”.

On that fateful October day, the Sun and Moon were aligned in such a way that their gravitational force on tides was larger than normal. However, the Moon was also closer to Earth than normal, which further amplified the force of the tide.

The perigean spring tide

This two-in-one combination of astronomical forces is known as a perigean spring tide, which leads to enlarged tides for a matter of days, and occurs just twice every 13 months. 

Analysis of the Earth and Moon’s orbits showed that Oct 14 1216 was the lunar perigee, when it is at its closest point to the Earth, just two days after the alignment of the moon and sun on Oct 12 in a new moon. 

“The astronomical and hydrographical calculations show that the tidal bore would have arrived near 4pm on Oct 12 1216,” Prof Olson told The Telegraph. 

“King John had the misfortune to attempt the crossing of The Wash on the day of a perigean spring tide. Perigean spring tides would have prevailed for a few days. A crossing a week before or a week after almost certainly would not have encountered destructive tides.”

Any other day but Oct 12...

Prof Olson said that had the king tried to cross at the same time of day at any other time, the rising tide would not have been so damaging and the Crown Jewels likely never lost.  

“King John and his baggage train happened to attempt a crossing over the sands of The Wash on a day with an unusually great tidal range,” he wrote in his book, Investigating Art, History and Literature with Astronomy.

“A new moon fell exactly on that day. Moreover, this date was near the time of lunar perigee, when the Moon is closest to Earth and exerts the greatest tide-raising forces on Earth’s oceans. 

“This unusual lunar configuration produced perigean spring tides and the tidal bore that caused the loss of the Crown Jewels.”