The plain of the Po, named for the Lombards who ruled it from Pavia, and in the twelfth century the densest network of self-governing cities in Europe — the Lombard League that fought Frederick Barbarossa.
Lombardy is the fertile plain between the southern Alps and the river Po, watered by Alpine rivers and crossed by the roads running from the passes down to Milan, Pavia and the Adriatic. It takes its name from the Lombards, the Germanic people who entered Italy in 568 and ruled most of the peninsula from Pavia until Charlemagne deposed their last king in 774.
Its medieval importance is a matter of density. No comparable area of Europe held so many large, rich and independent cities so close together, and the contest between those cities and whoever claimed to rule Italy dominates the region's history from the eleventh century to the thirteenth.
After 774 the Lombard kingdom became the kingdom of Italy under Frankish and then German kings, and the Iron Crown at Monza remained the symbol of that title. But the kings were mostly absent, and real authority settled on bishops and then, from the late eleventh century, on sworn associations of citizens — the communes.
By about 1100 Milan, Cremona, Brescia, Bergamo, Piacenza, Lodi and their neighbours were governing themselves through elected consuls, minting coin, waging their own wars and quarrelling ferociously with one another. They did not deny that the emperor was their lord; they simply did not expect him to exercise it.
Frederick I Barbarossa was not prepared to accept that. At the Diet of Roncaglia in 1158 he had jurists define the imperial regalia — tolls, mints, courts, the appointment of magistrates — and claimed them all back. When Milan resisted he besieged it and in 1162 destroyed the city, dispersing its people into four settlements.
The response came in stages: the Veronese League of 1164 in the east, and then on 7 April 1167 the oath of Pontida, which bound the Lombard cities together in the Lombard League. Milan was rebuilt, and in 1168 the allies founded a new fortress city in the west and named it Alessandria after Pope Alexander III, the emperor's other great opponent. On 29 May 1176 the league's infantry and the Company of Death held the imperial cavalry at the Battle of Legnano and broke it, in one of the very few medieval battles in which communal militia defeated a feudal army outright.
Legnano forced negotiation. The Truce of Venice in 1177 reconciled Frederick with the pope, and the Peace of Constance on 25 June 1183 settled the cities' position: they acknowledged imperial overlordship and paid for it, and in exchange kept their consuls, their courts, their walls and their leagues. It is the clearest formal recognition of urban self-government anywhere in twelfth-century Europe.
The quarrel revived under Frederick's grandson. The league re-formed against Frederick II, who beat it heavily at the Battle of Cortenuova in 1237 and captured its carroccio, the ox-drawn war-altar that carried each city's standard. His fortunes turned at Parma in 1248, when the besieged citizens broke out and sacked the imperial camp while he was hunting, and the league outlasted him: he died in 1250 and it dissolved shortly afterwards, its cities effectively independent.
The wealth underneath the politics came from water, wool and trade. Irrigation works — many of them monastic in origin, later extended by the communes — made the plain one of the most productive agricultural regions in Europe, and the cities worked wool and fustian and later silk.
Lombard merchants financed that trade and then other people's. They were lending across the Alps from the twelfth century, and "Lombard" became a general European word for a moneylender and a pawnbroker, surviving in street names from London to Amsterdam. In the fourteenth and fifteenth centuries Milanese workshops became the leading armour producers of Europe, exporting harness to England, France and Spain.