Papal politics of the mid-17th century were complicated, with frequently shifting military and political alliances across the
Catholic world. While it is difficult to trace the precise origins of the feud between the duchy of Parma and the papacy, its origins can be looked for in political maneuverings occurring in the years or even decades preceding the start of military action. In 1611 a group of
conspirators,
nobles from
Modena and
Mantua, was accused of devising a plot to
assassinate Ranuccio I Farnese, Duke of Parma and other members of the
Farnese family in
Parma. In reality, the plot had been
"uncovered" when a prisoner (being held for unrelated crimes) confessed to it and implicated members of various noble houses. Though the accusations were likely untrue, 100 of the
"conspirators" were
tortured and eventually
executed in Parma's main square in 1612. Many of their estates were confiscated leaving a large number of now legitimately discontented nobles. Until his death in 1622, Ranuccio remained paranoid about future assassination attempts and about curses from
witches and
heretics. He persecuted "witches" and alleged conspirators savagely and even had his own mistress,
Claudia Colla, burned to death. He remained convinced that other noble families were plotting his downfall. However, tensions between the Farnese and other Italian nobility were not limited to local events in Parma. Historian
Leopold von Ranke gives an account of a 1639 visit to
Rome by
Odoardo Farnese, Duke of Parma and
Piacenza. The Duke arrived in Rome to great fanfarehe was given gifts and escorted around the city by Pope Urban's
Cardinal-nephews,
Antonio Barberini and
Francesco Barberini. But the Duke refused to pay due deference to the Pope's other nephew; the newly appointed
Prefect of
Rome,
Taddeo Barberini. As the Duke prepared to leave, he suggested that an escort from the city (ordinarily reserved for the
Grand Duke of Tuscany) would be appropriate. Francesco Barberini refused. The Duke took his leave but urged the Pope to chastise both Cardinal-nephews. The nephews were furious and convinced the pope to punish the Duke by banning grain shipments originating in Castro from being distributed in Rome and the surrounding territory, thereby depriving the Duke of an important source of income. Duke Odoardo's Roman creditors saw their chancethe Duke was unable to pay his debts, which he had accumulated in military adventures against the
Spanish in
Milan and in luxurious living. The unpaid and unhappy creditors sought relief from the pope, who turned to military action in an attempt to force payment. ==Preparations for war==