I'm using the PHP wrapper with PrinceXML 12.5 and the options I'm using don't seem to be working. For example, I've tried various examples of:

$prince->setPageMargin('.5in'); //tried 1in, 20mm, 50mm, etc.
$prince->setPageSize('legal'); //tried letter, legal, 8.5in 14in, etc.

Yet the margins and page size never change. Is there a trick to doing this?

Are there any CSS @page rules that could be overriding them?

Yes, that was it. I didn't realize that I was include an external CSS which had set those attributes. Thanks!