In 1354 Galeazzo II Visconti was appointed as feudal lord of the territory, which he divided into four districts called "squadre" (Sesia, Agogna, Inferiore and Ticino) for a more thorough control of taxes and mercenary troops. In 1361 the province was sacked by a Societas Anglicorum, armies of English mercenaries, also called the White Army from the colors of the uniforms, led by condottiere Albert Sterz, finally defeated by Luchino dal Verme.
In July 1468 Galeazzo Maria Sforza married Bona di Savoia, and this wedding marked the beginning of the Savoy influence. A terrible plague in the years 1629 and 1630 stormed the area, already decimated by a famine in the two previous years. When the plague was over, there was a gradual rise in population and improvements in the agricultural techniques. Finally the Spanish domination ended in 1706, when the area came under Austrian control, to pass finally under the Savoy in 1734.
The new rulers introduced administrative and social reforms, which paved the way to the more important agricultural reform of the 1850's under the influence of the wise minister and entrepreneur Camillo Benso Count of Cavour (1810-61), one of the greatest political figures in Italian history.
Cavour ordered the construction of canals in the plain of Novara, and introduced the reforms and projects that he had already successfully tried on his own lands, and developed the cultivation of rice, of which the province is one of the major rice producers.