Which preposition to use with freethought

in Occurrences 2%

The victims have been either poor, uneducated people, or men who propagated freethought in a popular form.

among Occurrences 1%

If we take the cases in which the civil authorities in England have intervened to repress the publication of unorthodox opinions during the last two centuries, we find that the object has always been to prevent the spread of freethought among the masses.

over Occurrences 1%

The triumph is not one of Freethought over Christianity, nor is it over the House of Commons; it is the triumph of law, brought about by good menof all shades of opinion, but of one faith in justiceover Tory contempt of law and Ultramontane bigotry.

Which preposition to use with  freethought