Italy in the 12th and 13th centuries was vastly different from Europe north of the Alps (feudal Europe). The Peninsula was a melange of political and cultural elements rather than a unified state.
Marc Bloch and Fernand Braudel argue that geography determined the history of the region. Because an attack across the Alps was very difficult, German overlords could not exert continuing control over their Italian vassal states and Italy was thus substantially freed of German political interference. No strong monarchies emerged as they did in the rest of Europe; instead there emerged the independent city-state.
Within the peninsula there was great physical diversity. Italy was cut into numerous small regions by mountains and communication between them could be very difficult. The Po plain was an exception; it was the only large contiguous area, and most city states which fell to invasion were on the Po plain. Those that survived longest were in the more rugged regions, such as Florence.
There was a strong continuity of urban awareness in northern Italy which in the rest of Europe had virtually disappeared. Some cities and their urban institutions had survived in Italy since the Dark Ages. Many of these towns were survivors of earlier Etruscan towns which had existed within the Roman Empire. The republican institutions of Rome had also survived the Dark Ages. Some feudal lords existed with a servile labour force and huge tracts of land, but by the 10th century, Venice had become a large trading metropolis.
While those Roman, urban, republican sensibilities persisted, there were many movements and changes afoot. Italy first felt the changes in Europe from the 11th to the 13th centuries. Typically there was:
By the 13th century, northern and central Italy had become the most literate society in Europe. Fifty per cent of the male population could read in the vernacular, as could a small but significant proportion of women.
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 most places where communes arose (e.g. Britain and Flanders) they were absorbed by the monarchical state as it emerged. Almost uniquely they survived in northern and central Italy to become independent city-states. The breakaway from their feudal overlords by these communes occurred in the late 12th century during the Investiture Controversy between Pope and Emperor.
By the late 12th century, a new and unique society emerged; rich, mobile, expanding, with a mixed aristocracy, interested in urban institutions and republican government. Many city-states housed a violent society based on family, confraternity and brotherhood.
By 1300, most of these republics had become princely states. The exceptions were Venice, Florence, Bologna, Lucca, and a few others, which remained republics in the face of an increasingly monarchic Italy and Europe.