A previously unseen letter written by Admiral Lord Nelson from HMS Victory has gone on public display.
In the letter, sent in October 1804, Nelson tells the 2nd Earl of Camden why Camden's nephew left his ship only a few months after joining the navy.
The document, in which Nelson writes of his own battle with seasickness, was sent to Lord Camden's home at Bayham Abbey estate, near Frant, East Sussex.
It has gone on display at Tunbridge Wells Museum.
In the letter, which was found recently in the Camden family archives, Nelson also discusses the military and political situation with Lord Camden, who was secretary of state for war and the colonies at the time.
Writing about the aristocrat's nephew, Nelson tells Lord Camden that 16-year-old Francis James left HMS Victory because he was not suited to naval life and suffered from seasickness - a condition he could sympathise with.
He wrote: "I am ill every time it blows hard and nothing but my enthusiastic love for the profession keeps me one hour at sea."
A spokeswoman for Tunbridge Wells Museum said the letter was "hugely important because of its historical context".
She added: "The letter was written in October 1804 from HMS Victory in the Mediterranean where Nelson was permanently stationed to counter French influence.
"This was just a year before his great victory - and death - at the Battle of Trafalgar.
"The letter links Admiral Horatio Nelson with the local noble Camden family who lived on the Bayham Abbey estate.
"It also gives a fascinating insight into the character of this great naval hero."
The letter will be shown at the museum from about a month from Monday.
In November a letter from Nelson to his lover Lady Emma Hamilton was sold at auction for £20,000.