Which preposition to use with unfounded

in Occurrences 7%

The truth is, however, that they are both well known to have been utterly unfounded in fact.

as Occurrences 3%

But arrogant and unfounded as was the claim of Leo,that Peter, not Christ, was the rock on which the Church is founded,it was generally accepted by the bishops of the day.

than Occurrences 2%

I will only add, that, come into vogue as it might have done, there is no opinion more unfounded than the very general one among adults, that children should be uniformly grave; and that just in proportion as they laugh and appear frolicsome, just in the same proportion are they out of the way, and deserving of reprehension.

Which preposition to use with  unfounded