Matteo was appointed numerous times as Imperial Vicar over the whole of Lombardy, while expanding, with the assistance of his sons, his sphere of influence to Piedmont, Emilia, Bologna, and Genoa.

[6] Following the death of William VII, Marquess of Montferrat in 1292, Matteo expanded his influence westward, taking Casale, gaining the lordships of Novara and Vercelli, and the captaincy of Alessandria.

[7] Matteo managed to remain at the helm of the city until June 1302, when Guido della Torre again took the lordship of Milan, through a league formed by the Torriani and the anti-Visconti families of the cities of Cremona, Pavia, Piacenza, Novara, Vercelli, Lodi, Crema, and Monferrato led by Alberto Scotti and Ghiberto da Correggio.

[9] In 1311, Matteo met the German King Henry VII at Asti and from this, received a mandate to reach a peace agreement in Lombardy.

[11] However, on 12 February, German soldiers of Henry VII faced an armed Torriani force, led by Guido della Torre, who did not accept the treaty between their cousin Cassone and Matteo.

[13] They then organized a league that included Milan, Como, Novara, Vercelli, Bergamo, Brescia, Lodi, Cremona, and Piacenza, which had all become Ghibelline cities loyal to the Emperor.

[15][16] He commissioned a fresco in the main hall of the castle which illustrated the victory of the Visconti family over Napoleone della Torre at the battle of Desio.

[19] The pope appointed two emissaries, Bernard Gui and Bertrand de la Tour, to investigate the Ghibelline areas of Milan, Lombardy, and Romagna.

[25] During this time, the papal legate, Cardinal Bertrand du Poujet, proclaimed from Asti a holy crusade against the Visconti.

[28] In December, the Pope asked his appointee, the de jure Archbishop of Milan, Aicardo da Camodeia, to open a new case of heresy against Matteo and his son, Galeazzo.