the large territories of the Patriarchate of Aquileia were divided between the Republic of Venice and the Holy Roman Empire, but historically a Venetian was chosen as patriarch despite the opposition of the Emperor. Agostino Gradenigo was secretly chosen by the Pope as coadjutor bishop with the right of succession to the Patriarch of Aquileia and the Venetian Senate was informed on 27 January 1624. The nomination as coadjutor was sent secretly to the Nuncio in Venice on 20 March 1627, but was made public only later the death of the previous Patriarch, Antonio Grimani, on 26 January 1628.[3]
Emperor Ferdinand II strongly opposed this appointment, forbidding, on 12 February 1628, all his subjects from recognizing Agostino as Patriarch, and forbidding, on 12 April, Agostino from entering the territories of the patriarchate governed by the Empire. However, Agostino, accompanied by men in arms, entered Udine (the actual capital con the Patriarchate, under the Venetian government) on 30 May 1628.[1]
When Agostino was asked to indicate a own coadjutor bishop with the right of succession he suggested to appoint a bishop able to speak German, and he also suggested it in a letter to the Pope. The government of Venice summoned him to express its disgust at that proposal.[1] Finally on 11 September 1629, when Agostino was already ill in Padua (probably of malaria), he decided to appoint as successor his distant relative Marco Gradenigo, and this time the Venetian Government accepted (15 September), and the Pope confirmed that decision on 22 September.
Agostino Gradenigo died in Padua in the night between 25 and 26 September 1629, and he was buried in the church of San Zaccaria in Venice.[3]