During the Renaissance up to Napoleon, Italy's various regions would revolve around one main city-state who would be considered the main power within. The south was dominated by Naples; Lazio, Umbria, and Marche by Rome; Milan held most of Lombardy; Liguria was dominated by Genoa; Tuscany was Florence-centric after the fall of Siena; Venice had Venetia and Friuli; Piedmont was centered on Turin, the functional Savoyard capital. The exception to the rule is Emilia. Emilia had Ferrara dominating Modena and Reggio, but it was seized by the Pope after the last Este died with no heir. Parma was held by Milan during the Renaissance, only being freed after a period of Papal domination. The other big city in the area, Bologna, was under Papal control the whole time.
With a PoD of after 1200, which of these cities had the best chance of uniting the Emilia region? What troubles would it face in unification? How might this impact the history of neighboring city-states?