<P> Northern Italy and upper Central Italy were divided into a number of warring city - states, the most powerful being Milan, Florence, Pisa, Siena, Genoa, Ferrara, Mantua, Verona and Venice . High Medieval Northern Italy was further divided by the long - running battle for supremacy between the forces of the Papacy and of the Holy Roman Empire: each city aligned itself with one faction or the other, yet was divided internally between the two warring parties, Guelfs and Ghibellines . Warfare between the states was common, invasion from outside Italy confined to intermittent sorties of Holy Roman Emperors . Renaissance politics developed from this background . Since the 13th century, as armies became primarily composed of mercenaries, prosperous city - states could field considerable forces, despite their low populations . In the course of the 15th century, the most powerful city - states annexed their smaller neighbors . Florence took Pisa in 1406, Venice captured Padua and Verona, while the Duchy of Milan annexed a number of nearby areas including Pavia and Parma . </P> <P> The first part of the Renaissance saw almost constant warfare on land and sea as the city - states vied for preeminence . On land, these wars were primarily fought by armies of mercenaries known as condottieri, bands of soldiers drawn from around Europe, but especially Germany and Switzerland, led largely by Italian captains . The mercenaries were not willing to risk their lives unduly, and war became one largely of sieges and maneuvering, occasioning few pitched battles . It was also in the interest of mercenaries on both sides to prolong any conflict, to continue their employment . Mercenaries were also a constant threat to their employers; if not paid, they often turned on their patron . If it became obvious that a state was entirely dependent on mercenaries, the temptation was great for the mercenaries to take over the running of it themselves--this occurred on a number of occasions . </P> <P> At sea, Italian city - states sent many fleets out to do battle . The main contenders were Pisa, Genoa, and Venice, but after a long conflict the Genoese succeeded in reducing Pisa . Venice proved to be a more powerful adversary, and with the decline of Genoese power during the 15th century Venice became pre-eminent on the seas . In response to threats from the landward side, from the early 15th century Venice developed an increased interest in controlling the terrafirma as the Venetian Renaissance opened . </P> <P> On land, decades of fighting saw Florence, Milan and Venice emerge as the dominant players, and these three powers finally set aside their differences and agreed to the Peace of Lodi in 1454, which saw relative calm brought to the region for the first time in centuries . This peace would hold for the next forty years, and Venice's unquestioned hegemony over the sea also led to unprecedented peace for much of the rest of the 15th century . In the beginning of the 15th century, adventurer and traders such as Niccolò Da Conti (1395--1469) traveled as far as Southeast Asia and back, bringing fresh knowledge on the state of the world, presaging further European voyages of exploration in the years to come . </P>

What contributed to the growth of the arts in italy during the renaissance