Although the presence of the enemy in the surroundings was already known to both sides, they met suddenly without having time to plan any strategy. The Battle of Legnano was crucial in the long war waged by the Holy Roman German Empire to try to assert its power over the municipalities of northern Italy, who decided to put aside each other's rivalries by allied themselves in a military-led union symbolically by Pope Alexander III, the Lombard League, whose symbol was the Carroccio.