Uppercase noupppercase in header

[Robert Neumann]

Hello,
I am using the fancyhdr package with the commands
\fancyhead [RO,LE]{ \slshape \leftmark}
to print the pagenumber in the header.
But I would like to have "normal" with no uppercases. I cannot figure out what 
to insert, since I'm sure there is a very simple solution. 
(Yes, I'm a newbie)
Thanks
Robert