LONDON, England (CNN) -- An American professor doing research in London stumbled across a series of previously unknown letters written by, to, and about Benjamin Franklin, a stunning find that sheds new light on early U.S. history. 

The letters cover Benjamin Franklin's success in dealing with a British general. 

The collection of 47 letters are hand-written copies made 250 years ago, when Franklin lived in London. That they were filed under the copyist's name, not Franklin's, may explain why they were overlooked by historians until now, said a curator at the British Library, where the letters are held. 

The find is reported in the April issue of the William & Mary Quarterly, a journal of early American history and culture. 

The letters are important in large part because they offer a "wealth of new details" that affect modern understanding of Franklin, writes Alan Houston, the political science professor who discovered the letters in the spring of 2007. 

They also raise the question of how many other documents remain waiting to be found on Franklin and his life. 

Houston, a professor at the University of California at San Diego, discovered the letters on the last day of his last research trip to London, just before the library's closing time. 

"The first item was a letter from Benjamin Franklin to the secretary of the governor of Maryland, and I looked at it and I started to read, and I thought, 'This doesn't look familiar,'" Houston told CNN. "I've read everything Franklin ever wrote." 

Now, provide a numbered list of answers to these questions:

1. Where did he teach?
2. what was taught?
3. When were the letters found?
4. What publication reported the correspondence?
5. Which issue?
6. What type of publication is it?
7. Who was the author of the letters?
8. Was there anything remarkable about them?
9. What was the subject?
10. who was the first letter found addresses to?
11. was the professor familiar with Franklin's writing?
12. Who did he relate that to?
13. Were the found letters actually written by Franklin?
14. How long ago?
15. Where was Ben living at the time?
16. How come the letters were not found sooner?
17. According to whom?
18. Where?
19. Did they reveal anything new?
20. what day were they found?

Numbered answers:
1. University of California at San Diego,
2. U.S. history.
3. spring of 2007.
4. William & Mary Quarterly,
5. April issue
6. a journal of early American history and culture.
7. written by, to, and about Benjamin Franklin
8. They shed new light on early U.S. history.
9. Benjamin Franklin's success in dealing with a British general.
10. The governor of Maryland
11. Yes
12. CNN
13. They were hand written copies
14. 250 years ago,
15. London.
16. They were filed under the copyist's name,
17. A curator
18. British Library
19. Yes
20. The last day of his last research trip to London