Which preposition to use with overstate

in Occurrences 1%

By the one side the distinction was strongly insisted on between mere instruction and education, the distinctly religious character of the University education was not perhaps overstated in its theory, but portrayed in stronger colours than was everywhere the fact; and assertions were made, which sound strange in their boldness now, of the independent and constitutional right to self-government in the great University corporations.

Which preposition to use with  overstate