<P> The Italian city states were also highly numerate, given the importance of the new forms of bookkeeping that were essential to the trading and mercantile basis of society . Some of the most widely circulating books, such as the Liber Abaci by Leonardo Fibonacci of Pisa, included applications of mathematics and arithmetic to business practice or were business manuals based on sophisticated numeracy . </P> <P> Indeed, Luca Pacioli helped create the banking system of the Italian city - states with double - entry bookkeeping . His 27 - page treatise on bookkeeping contained the first known published work on that topic, and is said to have laid the foundation for double - entry bookkeeping (of Genoese merchants) as it is practiced today . </P> <P> During the 11th century in northern Italy a new political and social structure emerged: the city - state or commune . The civic culture which arose from this urbs was remarkable . In some places where communes arose (e.g. Britain and France), they were absorbed by the monarchical state as it emerged . They survived in northern and central Italy as in a handful of other regions throughout Europe to become independent and powerful city - states . In Italy the breakaway from their feudal overlords occurred in the late 12th century and 13th century, during the Investiture Controversy between the Pope and the Holy Roman Emperor: Milan led the Lombard cities against the Holy Roman Emperors and defeated them, gaining independence (battles of Legnano, 1176, and Parma, 1248; see Lombard League). </P> <P> Similar town revolts led to the foundation of city - states throughout medieval Europe, such as in Russia (Novgorod Republic, 12th century), in Flanders (Battle of Golden Spurs, 14th century) in Switzerland (the towns of the Old Swiss Confederacy, 14th century), in Germany (the Hanseatic League, 14th--15th century), and in Prussia (Thirteen Years' War, 15th century). </P>

Who did the lombard league give the most power to