The clearest and most effective strategy to win in Pax Ren is the bring about and Anarco-Communist Revolution. This can be quite challenging to carry out prior to industrialization but is a repeatable strategy if you can mill through the decks to find Both Marx and Engels. Once you have both in your tableau simply began a Communist revolution in whatever kingdom has the most repressed peasants (concessions). With a single kingdom toppled the rest will fall swiftly, ending the capitalist era in its infancy just as predicted by Pre-Marxist philosophy