How can I change text to a serif font?

[Steve]

I have Lilypond 2.6.4 installed in Cygwin (this is the latest version 
available in Cygwin). Previous versions always used a serif font for all the 
text, but now the titles, footers, and rehearsal marks are in a sans serif 
font. I prefered the serif font. How can I change the default for text back to 
a serif font, or could a problem with my configuration cause this? If there is 
any configuration information you need to see, please let me know, but I 
expect something about how to make global font changes first.

I have tried this in the \paper block, but it doesn't change the font used. I 
got it from an example, but I don't entirely understand what it does:

    #(define text-font-defaults
      '((font-encoding . latin1)
        (baseline-skip . 2)
        (word-space . 0.6)))

    #(set! fonts (make-century-schoolbook-tree 1.0))


Steve