Which preposition to use with feoffees

of Occurrences 1%

He is a Lieut.-Colonel, an O.B.E., and, what is more important still, one of the feoffees of Buckley's Hospital (a fifteenth-century foundation here), and whatever a feoffee may be he is not the kind of man to toy with in a small town like this.

Which preposition to use with  feoffees