Which preposition to use with unindebted

to Occurrences 1%

I liked an occasional visit to our little club, where the exciseman, of fifty years standing was our oracle in politics; the attorney, of about the same duration, gave us opinions on the drama, philosophy, and poetry, all equally unindebted to Aristotle; and my mild and excellent father-in-law, the curate, shook his silver locks in gentle laughter at the discussion.

Which preposition to use with  unindebted