The latinesque phrase Non plus ultra is well-known to historians of
early modern science, because its antithesis—Charles V’s imperial motto, Plus
ultra—was a familiar catch-cry for the new science. But there is much confusion
about the origins of these expressions. One common account supposes some
version of the negative tag to have been a standard classical motto, an injunction
perhaps, attached to the Pillar of Hercules. This phrase was later inverted
to provide the Imperial device (so goes this explanation) and the resulting positive
phrase was interpreted as celebrating colonial expansion across the
Atlantic. Rosenthal, however, has convincingly undermined this whole story:
the ancient motto it posits simply did not exist; the modern was coined before
Charles acquired his association with America.
The present work refines Rosenthal’s argument. I uncover classical sources for
the early modern motto, by invoking a more satisfactory version of the inversion
thesis. I agree there was no set negative adage, but insist there was a set
idea, occuring repeatedly, in texts quite familiar to the Renaissance. This idea is
set in contexts that display a popular Urbild of the successful conqueror, and is
eventually projected onto Alexander. So it is an ideal source for imperial propoganda.