The Cortenova family sided with the Pope and the Lega Lombarda, on the Guelph side, and allied with Milan and Brescia; that caused the angry reaction of Bergamo (which was on the Ghibelline side) . However, some counts of Cortenova managed to hold important political positions in the Guelph cities of northern Italy. Zilio from Cortenova was imperial vicar and consul of Bergamo in 1193 and in 1203 he was mayor of Verona, Maffeo from Cortenova was judge in Milan in 1207 and Podestà of Brescia in 1227, Egidio I from Cortenuova was mayor of Brescia in 1236, Manfredo from Cortenuova was mayor of Verona in 1227 and of Milan in 1234.
The situation worsened with the beginning of the clashes between Frederick II of Swabia and the municipalities of the Lega Lombarda; many battles were fought and one of the most famous was fought in Cortenuova, on 27 November 1237.
In this famous battle two of the greatest armies of the Middle Ages clashed: Frederick II of Swabia and the second Lega Lombarda lined up their soldiers for a total of about 35,000 men. The League army was stalling, sure that the emperor would surrender with winter approaching. Frederick II, however, understood the situation and slily pretended a retreat towards the allied Cremona. Meantime in Cortenuova he held an ambush to the enemy coalition of Milan and Brescia, which was unprepared and deceived by the feigned retreat. Frederick II attacked the enemies who failed to organize a viable defense. The battle ended with the victory of the Ghibellines, which led to the destruction of the Guelph army. The next day the emperor razed Cortenuova. The surviving Cortenovesi went to populate the nearby villages of Romano, Martinengo and Cividate and the city of Cortenuova passed into the hands of the Municipality of Bergamo which forbade the repopulation. For this reason, it remained practically uninhabited until the half of the XV century.
In 1454 it became part of the feud of Bartolomeo Colleoni, which started the rebirth of the village. He built some rural buildings on the ruins of the castle destroyed in 1237 to accommodate farmers who had to cultivate the surrounding lands. In 1575 Cortenuova had about 300 inhabitants. The population remained stationary until 1951,when it began a slow decrease due to emigration to the industrial centers; since 1976 the opening of several factories has favoured the economic and demographic recovery.
As a commemoration of this important historical event, a monument was built in Cortenuova in 1987 on the 750 th anniversary of the Battle of Cortenuova (1237) in Aldo Moro Square. The location of the square is thought to be the exact place where the carroccio of the Lombard League was set during the famous battle. The monument has been designed by the architect Adolfo Ragionieri. The monument rises inside a bed with a diameter of m. 9.00 completely made of iron laminated type Fe42 protected by transparent paint. It has 20 curved iron lances (cut by blowtorch) arranged circularly, m. 4.30 high and with a thickness of 15mm, surrounded by two rings of sheet metal, an upper one and a lower one; in the upper one there are chiseled shields, on the lower one the coats of arms of the municipalities that took part in the battle: 18 of 10 of the Guelph municipalities of Milan and the Lega Lombarda and 8 Ghibelline municipalities. Finally, there are white and black pebbles at the base of the mound, symbolically reminiscent of the fallen in battle.
R. Caproni, Cortenuova, Pagazzano 1977.
R. Caproni, Cortenuova e la battaglia del 27 novembre 1237, Cortenuova 2007.
A. Ragionieri, Monumento commemorativo della battaglia di Cortenuova, Relazione tecnica, allegato A2, 1987.