Captain Robert Scott's diary from 1910 led Spink's July 13 autograph auction in London, achieving £16,000 ($21,139).
It's written in Scott's own hand and details the preparations for the ill-fated Terra Nova expedition (1910-1913).
He includes his appointments with various dignitaries, including the king and the prime minister, and his trips to purchase provisions such as sledges and cold-weather clothing.
Scott's expedition famously ended in disaster. A team of Norwegians beat him to the South Pole and he and four of his men died on the return journey to their ship.
His famous journal was recovered from his frozen body and is housed in the British Library.
The last entry, written while a blizzard roared around his tent, reads: "I do not think we can hope for any better things now. We shall stick it out to the end, but we are getting weaker, of course, and the end cannot be far.
"It seems a pity, but I do not think I can write more… For God's sake look after our people."
A 1681 letter from the Welsh privateer Sir Henry Morgan sold for £14,000 ($18,497).
It was written in Cuba and is addressed to the British naval board. It concerns the capture of a number of "villanous Pyrates".
Morgan (1635-1688) spent his salad days raiding Spanish settlements in the Caribbean, acquiring a reputation for extreme ruthlessness.
He was serving as lieutenant governor of Jamaica when this letter was written.
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