I'm curious if someone here is a bigger history nerd than me and might be able to help me out: The claim that San Marino is the world's oldest Republic links t

I'm curious if someone here is a bigger history nerd than me and might be able to help me out: The claim that San Marino is the world's oldest Republic links to a Wikipedia list which cites 301 as its transition date to Republic, however digging deeper that seems to be the founding date of the settlement of San Marino, with the earliest date relating to a Republic I could find being 1243 (the establishment of the Captains Reagent as the heads of state). Does anyone know more about the transition to republic? 1243 would still make it several centuries older than any other extant Republic, but significantly shorter lived than my personal favourite the Republic of Venice (697-1797, 1100 years of uninterrupted Republic).