Why is it called 'The Hague' and not Hageville or Haguedam?

Factual Questions
1

The subject says it all…

2

http://home-2.worldonline.nl/~aarde01/holland.htm#Den%20Haag%20or%20’s-Gravenhage

3

Previous thread on the topic, along with observations concerning other article-possessing place names.

http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=109004