This open friendship of Farnese for the people, at a time when the lords were everywhere practising great severity, added to the hatred of the imperial agents and whetted their desire for vengeance. There was still another cause of quarrel. The port of the Po at Piacenza had been ceded by Paul III. to the divine Bonarotti (taking away certain rights upon it from the Pusterla and Trivulzio) and Bonarotti had rented it to Francesco Durante, and the nobles taking the sides of the defrauded parties resolved to wreak their vengeance on the pontiff’s son. A conspiracy was formed at the head of which were Giovanni Anguissola, Camillo and Gerolamo Pallavicini and Giovanni Confaloniere. But the soul of the plot was count Agostino Landi, the same person who informed the government at Lucca of the conspiracy of Pietro Fatinelli, and thus betrayed him to death. Andrea opened his heart to Landi and showed him the golden promises of Cæsar. Casoni relates this and he founded it upon irrefragible proofs which he had in his hands. He adds that the prince pledged to Landi the hand of the sister of Gianettino for his son with a wealthy dowry. This marriage afterwards took place. It was important that, after the assassination of the duke, the duchy of Piacenza should revert to the empire, and to secure this result Doria intrigued with Gerolamo Pallavicino, Marquis of Cortemaggiore and Busseto, whose mother and wife had been held in captivity by Farnese and who was therefore anxious to punish the affront. The conspirators in Piacenza at first really intended to establish a popular government; but Doria adroitly induced them to communicate with Gonzaga. It was not difficult then to secure the subjection of Piacenza to the empire. A warm animosity burned between Gonzaga and the duke on account of the priorship of Barletta which Gonzaga had obtained for his son to the exclusion of Horace Farnese. Gonzaga made many attempts upon the life of Pier Luigi. Annibal Caro, who in July, 1547 was sent by the latter to Milan informed his master of these plots; but the duke had no presentiment of his imminent peril. The efforts of Gonzaga, however, all failed, and with the knowledge of Charles, he sent captain Federico Gazzino to order the conspirators to proceed with their work.