CASTRO, ALFONSO de: V. ALFONSO DI CASTRO.
CASTRO, GUERRA DI. — Pope Paul III had granted to his relatives, the Farnese, in addition to the possession of Parma, that of a small duchy in the Viterbese, called C. from its principal town, situated within the territories of the Papal States. In the time of Urban VIII the Barberini, avid nephews of the reigning Pope, viewed with disfavour the presence of outsiders at the gates of Rome; in turn Odoardo Farnese, Duke of Parma, had various reasons for resentment against the Pope and the new lords; under these conditions it was easy to find a casus belli and the war soon turned into a test of the political prestige of the State of the Church, involving all the other Italian States, eager to strike a blow at ecclesiastical power.
In January 1640 the Farnese placed Castro in a state of war; Urban demanded payment of the interest on credits that Roman bankers had granted him, secured by the Duke’s revenues. Upon refusal, the Pope ordered that traffic between Rome and Tuscany be diverted from the road passing through C. and prohibited the export of grain; the rebel did not yield and open war ensued (end of 1641). Under the command of Marquis Luigi Mattei, the papal troops moved from Viterbo against C. and occupied it almost without a fight; followed the sequestration of Farnese’s allodial goods, including the palace in Rome. But, disregarding advice to moderate his actions, Urban VIII then wished to continue the campaign, turning against Parma and Piacenza, faithful dependents of the Holy See; the Italian powers, alarmed, formed a league and provided financial assistance. Thus Odoardo was able to march at the head of an army “against the Barberini,” he said, not against the Pope, and occupy Bologna, Imola, Forlì. In Rome there was already fear of a new sack, like that of Bourbon, but the Farnese was unable to take advantage of the fortunate circumstances. At this point the issue became entangled in the various European controversies and in the eternal duel between France and Spain, in the sense that the French ambassador in Rome sought to make peace only in order to direct Italian forces against the Duchy of Milan, which was held by the Spanish; in the spring of 1643 a league was concluded between Venice, Tuscany, the Este, and the Farnese to “restore Italian peace,” as was often repeated at the time, and in substance to extract the maximum advantage for each party amid great mutual distrust. Meanwhile the war continued, almost without human casualties but with great financial damage, until Mazarin tasked Cardinal Alessandro Bichi with conducting separate peace negotiations with the various parties to avoid the presence of Spain and the Empire in a general congress; a defeat of the papal troops at Lagoscuro at the hands of the Venetians (spring of 1644) hastened the conclusion. Territorial status quo ante was restored, but the moral position of the Pope, held to ransom by a rebellious dependent, was irreparably shaken; while Urban, after publishing the peace on 10 May 1644, died on 29 July of the same year.