The Lombard plain, located in the central part of Lombardy at the confluence of several Alpine passes, has for centuries been a much coveted and frequently invaded area, and it has been a battlefield in many wars. First inhabited by a Gallic people, the region became (3d cent. B.C.) part of the Roman province of Cisalpine Gaul. It suffered heavily during the barbarian invasions that took place toward the end of the Roman Empire. In A.D. 569 the region was made the center of the kingdom of the Lombards, for whom it was named. Lombardy was united in 774 with the empire of Charlemagne.
After a period of confusion (10th cent.), power gradually passed (11th cent.) from feudal lords to autonomous communes, and a general economic revival occurred. Trade between N Europe and the E Mediterranean was largely carried on via the Po valley, and Lombard merchants and bankers did business throughout Europe. In the 12th cent. several cities united in the Lombard League in order to defy Emperor Frederick I, who wanted to assert his authority over the communes, and defeated him at Legnano (1176). The 13th cent. was marked by struggles between Guelphs (pro-papal) and Ghibellines (pro-imperial), which resulted in wars among cities and rivalries between families within cities. In the 11th–12th cent. there was a characteristic Lombard Romanesque architecture, and during the Renaissance Lombardy had a flourishing school of painting whose leading figures were Bernardino Luini and Gaudenzio Ferrari.
Except for Mantua (ruled by the Gonzaga family), Lombardy fell (14th–15th cent.) under the sway of the Visconti family and the Sforza dukes of Milan. However, Bergamo and Brescia (1428) and Cremona (1529) were lost to Venice and the Valtellina valley was taken by the Grisons (1512). After the end (mid-16th cent.) of the Italian Wars, the rest of Lombardy followed the fortunes of Milan. Spanish rule (1535–1713) was followed by that of Austria (1713–96) and of France (1796–1814). The Lombardo-Venetian kingdom was established under Austrian rule in 1815. Lombardy briefly ousted the Austrians in 1848–49; in 1859 they were permanently removed and the kingdom was dissolved.