Purple and gold is a combination that has been mentioned by more than one writer.

Lord George Gordon Byron (1788-1824) used the phrase as part of the description of an army that attacked the peoples of the Galilee region about two and a half millennia ago:

The Assyrian came down like the wolf on the fold,
And his cohorts were gleaming in purple and gold;
And the sheen of their spears was like stars on the sea,

The 21st century sees the combination proudly used by Covington Elementary School in Illinois.