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Doubt over date for Brit invasion | Doubt over date for Brit invasion |
(about 2 hours later) | |
Julius Caesar's invasion of Britain in 55BC could not have occurred on the dates stated in most history books, a team of astronomers has claimed. | |
The traditional view is that Caesar landed in Britain on 26-27 August, but researchers from Texas State University say this cannot be right. | The traditional view is that Caesar landed in Britain on 26-27 August, but researchers from Texas State University say this cannot be right. |
Dr Donald Olson, an expert on tides, says that the English Channel was flowing the wrong way on these dates. | |
An invasion of the south coast at Deal on August 22-23 is favoured instead. | |
The claims appear in the latest issue of Sky & Telescope magazine. | The claims appear in the latest issue of Sky & Telescope magazine. |
Caesar came to Britain with 100 warships and two legions comprising 10,000 men. But as he approached Dover's white cliffs, spear-wielding Celtic warriors lined up along the ridge, prompting the Roman leader to look for a better landing spot. | Caesar came to Britain with 100 warships and two legions comprising 10,000 men. But as he approached Dover's white cliffs, spear-wielding Celtic warriors lined up along the ridge, prompting the Roman leader to look for a better landing spot. |
He ordered his fleet to move along the coast, and after travelling about seven miles they came to "an open and flat shore". | He ordered his fleet to move along the coast, and after travelling about seven miles they came to "an open and flat shore". |
What has been a matter of some debate is whether Caesar sailed left or right and when exactly his armada landed. | What has been a matter of some debate is whether Caesar sailed left or right and when exactly his armada landed. |
Astronomical solution | Astronomical solution |
Caesar mentioned strong tides, a full Moon and an ocean current. The astronomers Edmund Halley and George Airy previously used this information to try to solve the problem. But they disagreed with each other's conclusions. | Caesar mentioned strong tides, a full Moon and an ocean current. The astronomers Edmund Halley and George Airy previously used this information to try to solve the problem. But they disagreed with each other's conclusions. |
Dr Olson identified August 2007 as a rare opportunity to investigate the question of when Caesar landed. | Dr Olson identified August 2007 as a rare opportunity to investigate the question of when Caesar landed. |
Caesar was greeted by lines of armed Celts on the white cliffsDuring this month, complex tidal factors involving the Moon and Sun would unfold in a near-perfect replay of those in August of 55 BC. So the researchers conducted an expedition to the south coast of England in order to investigate their idea. | Caesar was greeted by lines of armed Celts on the white cliffsDuring this month, complex tidal factors involving the Moon and Sun would unfold in a near-perfect replay of those in August of 55 BC. So the researchers conducted an expedition to the south coast of England in order to investigate their idea. |
On the day which corresponded closely to the traditional date for the invasion, Dr Olson carried out a basic experiment - dropping an apple into the sea off Deal pier at roughly the time of afternoon when Caesar described the fleet moving. | On the day which corresponded closely to the traditional date for the invasion, Dr Olson carried out a basic experiment - dropping an apple into the sea off Deal pier at roughly the time of afternoon when Caesar described the fleet moving. |
The apple floated south-west towards Dover, suggesting that the Roman fleet could not have travelled up to Deal from Dover on that day. | The apple floated south-west towards Dover, suggesting that the Roman fleet could not have travelled up to Deal from Dover on that day. |
"The English Channel was flowing the wrong way," said Dr Olson. | "The English Channel was flowing the wrong way," said Dr Olson. |
Caesar's account led the researchers to focus on a possible invasion date a few days earlier. | Caesar's account led the researchers to focus on a possible invasion date a few days earlier. |
On the day corresponding to the revised date of 22-23 August, the team chartered a sightseeing boat and took GPS readings to determine how the boat was drifting. | On the day corresponding to the revised date of 22-23 August, the team chartered a sightseeing boat and took GPS readings to determine how the boat was drifting. |
They found the boat was floating north-east towards Deal. | They found the boat was floating north-east towards Deal. |
The Texas team's revised date gives Caesar the ocean current he needed to manoeuvre right, proceed seven miles, and land with a falling tide near present-day Deal. | The Texas team's revised date gives Caesar the ocean current he needed to manoeuvre right, proceed seven miles, and land with a falling tide near present-day Deal. |
This is the beach preferred by most historians but rejected by tide experts in the past. A modified reading of Caesar's reference to the "night of a full Moon" also leads to the August 22-23 date, Dr Olson claimed. | This is the beach preferred by most historians but rejected by tide experts in the past. A modified reading of Caesar's reference to the "night of a full Moon" also leads to the August 22-23 date, Dr Olson claimed. |
"The scientists were right about the tidal streams and so were the historians about the landing site," he explained. | "The scientists were right about the tidal streams and so were the historians about the landing site," he explained. |