My INTP's intuition tells me that there is something right about
in numeris vires
Sorry but,
what follows is what you can find googling for "vis in numeris"
De numeris: MS Hannover, Landeskirchlichen Archiv D 10 Nr. 1 (PfA Bissendorf HS 20) ff. 186r-195v [inc: Quanta sit vis in numeris noverant hii
The beginning ('incipit' in latin, which is 'inc:' in the reference above) says: Those (they?) were aware of how much strength (how much value) is in numbers...
spiccioli.