How did the greatest contribution of Rene Descartes affect the 18th and 19th-century philosophy?

Question

Thank you for using the Jiskha Homework Help Forum. Here are some sites for you to peruse. When you have decided for yourself the most important contribution, post it and we will be glad to critique it:

1. http://en.wikipedia.org/wiki/Ren%C3%A9_Descartes

2. http://www.iep.utm.edu/d/descarte.htm

These sites will also prove useful.

http://www.rep.routledge.com/article/DA026

http://www.bartleby.com/65/de/Descarte.html