The breakdown of the popolo into clearly defined, legally distinctive factions is apparent by 1303, but the key year in this development is really 1306. Later privilege lists, such as those of 1310 and 1319, refer back to 1306 as the major point of change in early fourteenth century political and legal structures.
The 1310 and 1319 revisions of the privileges lists demonstrate how powerful a legal weapon privilege had become for the ruling faction. According to the provisions governing those privileges, a privileged person could make an accusation against a member of the opposition and his charge would have validity by his word alone. The enemy faction however, could not respond with counter- charges, since privilege carried with it immunity from investigation in assault cases.
As a result of this expanded concept of “privilege,” private accusation procedure in the early fourteenth century became primarily a legal weapon of the ruling faction. Consequently, accusation records from the 1280s and the early decades of the fourteenth century reflect very different patterns of law enforcement. In the 1280s assault cases dominated the private accusation procedure, with other types of cases such as property damages, trespass, the ignoring of court orders, and single-instance theft cases (frequently by servants of the household) also included, but to a much lesser degree. All socioeconomic levels of the established community turned to the courts and used the accusation procedure to settle their differences: Contadini, great as well as lesser guildsmen, individuals from the upper ranks of the urban elite, including magnates – all appear in the private accusation records, as accusor as well as accused. Occasionally a feud between prominent families would break out and temporarily dominate the private accusation records as charges and counter-charges were filed, as, for example, in 1286, when one incident provoked seven cases, comprising thirteen percent of the cases in one of the four notaries’ records. This incident, as usually happened, resulted in the acquittals of all concerned and demonstrates vividly how elite families in the 1280s used the law courts to contain the vendetta.
Sarah Rubin Blanshei, “Crime and Law Enforcement in Medieval Bologna” (1982)