Michele Viale-Prelà (29 September 1798 – 15 May 1860) was an aristocratic Catholic priest from Corsica, France, who served as a diplomat for the Holy See in Switzerland, Bavaria and Austria.

Michele Viale-Prelà was born in Bastia, Corsica, on 29 September 1798 to a notable family of Genoese origin.

[2] He became close to Prince Klemens von Metternich and supported his policies even when they differed from the interests of the Papal States.

After the Revolutions of 1848 he skillfully led the negotiations between the Austro-Hungarian Empire and the Holy See that were concluded in the mutually satisfactory agreement of 18 August 1855.

[6] On 18 September 1856 he was appointed Cardinal-Priest of the church of Santi Andrea e Gregorio al Monte Celio in Rome.

[3] He remained in Vienna until 1856 to see through the implementation of the agreement, and began to govern to diocese of Bologna, a papal dominion, around the end of 1856.

[5] During the Second Italian War of Independence the Austrian garrison in Bologna left early in the morning of 12 June 1859.

By the end of the day the papal colors flying in the squares had been replaced with the Italian green, white and red, the Cardinal Legate had left the city, and a group styling itself Bologna's provisional government had proclaimed its desire to join the Kingdom of Sardinia.