London, Jun 12 (IANS): A rare letter written in English by French emperor Napoleon Bonaparte has been sold at an auction for 325,000 euros ($400,000), BBC reported.

The sale at auction house Osenat in Fontainebleau, south of Paris, was more than five times the anticipated price for the unique letter.

Napoleon wrote the letter in March 1816 during his exile on the South Atlantic island of Saint Helena when he was trying to learn English.

The letter was a homework exercise Napoleon sent to an English teacher for correction and sealed with the imperial eagle wax stamp, RIA Novosti said.

The letter is full of errors. For example, one sentence says: "He shall land above seven day a ship from Europe that we shall give account from anything who this shall have been even to day of first january thousand eight hundred sixteen."

The letter is one of three such English-language letters by Napoleon that exists in the world, according to the auction organisers, and was bought by Paris' Museum of Letters and Manuscripts in a fierce bidding war.

Napoleon was exiled to Saint Helena after his defeat at the Battle of Waterloo in 1815. The former French emperor died in island exile May 5, 1821, aged 52.