So it's April 7th, 1167. Frederick Barbarossa is currently in Rome, where the Antipope Pascal will soon reaffirm his right to rule over Italy. Meanwhile, in the Abbey of Pontida (some ten miles west of Bergamo) the consuls of Milano, Lodi, Ferrara, Piacenza and Parma sign a pact with the "Veronese League" and unite their forces to remove the Emperor from Italy once and for all.

Sort of. It's very convenient to pick out very specific start dates for things There was a great study commissioned by order of the President of the Italian Republic in 1976 to celebrate the 800 years of the battle of Legnano that finally re-examined the source material properly. The "Oath of Pontida" most probably never happened, it's only referenced for the first time in 1505 by historian Bernardo Corio. And even if it did happen, it most definitely wasn't the first or the last alliance between Italian cities (also, Piacenza and Parma didn't join).

In 1154 and 1157 Frederick Barbarossa could count on a large contingent of Veronese soldiers, while various contingents from Cremona, Como, Ferrara, Lodi, Mantua, Novara and Pavia would come and go depending on which city Frederick was currently trying to subdue. However, after the second Diet of Roncaglia in November of 1158 Frederick expressly laid out what he demanded of the Italian Cities; even those loyal to him. None of them were happy. When Frederick returned to Italy in 1164, the Minor Council in Venice panicked, as they could no longer withstand the economic implications of the Po floodplain's instability. Luckily, the ruling council in the city of Verona though the same thing. The Venetian Doge met representatives of Verona, Vicenza, Padua and Treviso in Venice, and a defensive pact against the emperor's excursions in east of the Adige river was struck. The northeastern cities declared they recognized Alexander III and not Pascal as the legitimate Pontiff, making their opposition to the emperor all but proclaimed.

Soon after, the pro-Imperial Patriarch of Aquileia took advantage of the Emperor's presence in Italy and moved to subdue the nearby town of Grado. However, true to the pact of the "League of Verona", a Venetian Fleet appeared in defense of the city. A contingent of marines fell upon the Patriarch's camp and captured him along with 700 of his men. In the meantime, men from Verona, Vicenza, Padua and Treviso bearing Venetian arms and paid in Venetian gold barred the passage of an army loyal to the emperor over the rivers Adige and Po. The Imperial army was composed of Mantuans and Ferrarese commanded by the dissenting pro-imperial Montecchi (of Verona) and Da Camino (of Treviso). One look the the combined forces of the Veronese League over the river Po and the filo-Imperial forces withdrew without giving battle. The military leader of the Veronese League was Ezzellino of Romano. A powerful landholder, he held the important fiefs of Onara, Bassano, Godego, and his namesake fortress of Romano. Elected by both the councils of Treviso and Vicenza as Podestà, Ezzellino was a natural commander of men. His strong personality and power both in town and country anticipated the trend of later centuries whereby one family would dominate the others in local politics.

Frederick, sensing a difficult situation, returned to Germany for a year before returning to Italy in 1166 with a vengeance. But the situation was not easy. By now, all of Western Europe had recognized his archenemies Pope Alexander III as the true Vicar of Christ on earth. Limiting himself to sacking and raiding the countryside of the ever-disloyal cities of Bergamo and Brescia, Frederick kept well clear of the Adige River and made his way rapidly south through Lombardy. He first stopped in Bologna, where the Imperial Vicar had been assassinated in 1165. The city quickly submitted and offered him hostages. He then split his forces, personally laying siege to the important maritime city of Ancona (which had granted a large quarter to the Byzantines and was evaluating becoming a protectorate) while a large detachment under Reinald of Dassel marched on Rome. An army loyal Pope Alexander III raised by the Roman Senate met the Imperial army at the foot of Mount Porzio but suffered a resounding defeat. This didn't stop the Romans from mounting a savage defense of their city. Even after the city's walls were breached, the Roman commander Oddo Frangipani barricaded himself inside the Coloseum (at the time re-purposed as a fortress) while fighting continued all the way inside the gates of St. Peter. Even the High Altar was stained in blood. But it was all for naught, as on July 30th 1167 Antipope Pascal celebrated mass in St. Peter's. Soon after Frederick would abandon the siege of Ancona to enter the city of Rome defiantly wearing the Golden Circlet of the Roman Senators.

Pope Alexander III and his court had long since fled to Benevento, where he was protected by Margaret the Queen of Sicily. Margaret, regent for her underage son William II, has confirmed her late husband's pro-papist stance. However, she was in no position to provide military assistance to the Italian cities and the harrowed Pope. King William the Wicked had been dead for little over a year and the banished Tancred of Taranto has already returned to his County of Puglia. Although he professed loyalty to the young king, Margaret preferred to keep as many knights as possible with her in Palermo.

In his haste to reach Rome, Reinald of Dassel had marched straight through the swampy Roman campagna, exposing the army (him included) to disease. Although Frederick was so very close to finally marching on Sicily and subjugating all of Italy, the tired and sick state of his army along with the lack of support from Pisa and Genoa left him no choice but to march back north to the ever-loyal city of Pavia where he would spend the winter.

But the situation in Lombardy was not simpler. While the Emperor had been gallivanting in central Italy, Bergamo, Brescia, Cremona and Mantua had signed a pact to defend their territory from the emperor. The exiled Milanese citizens would join the "League of Bergamo" in March of 1166, while Lodi would join in May. By December, those Milanese patricians who had fled farther afield would also adhere, including the Podestà, or chief executive, Guido da Landiano, who had taken refuge in his eponymous fief. That same year the cities also resolved to contribute to the reconstruction of Milan. A big deal is Mantua's adherence, but an even bigger deal is Cremona's participation, as the Cremonese contingent of the Imperial army were not only present during Milan's siege and destruction in 1162, but had proposed the destruction of the city in the first place!

While the Mantuans probably joined right away because otherwise they would be threatened by the Veronese league immediately to the east and the League of Bergamo immediately to the west, the Cremonese 180 is a bit more complex. The city's Consul and Bishop were two brothers from the powerful Dovara family-Oberto and Egidio- and they were two staunch imperialists. But in the summer of 1166, as soon as the Cremonese men-at-arms followed the emperor south to Rome an obscure and estranged Dovara family member called Anselmo da Dovara who was leader of the Cremonese dissidents rode into the city and riled the populace against the emperor. Egidio, commanding the Cremonese contingent of the Imperial army, has no choice but to return to the city. Alone against Anselmo who could count on the support of the Milanese as well as the citizenry, the Dovara brothers yielded to the League of Bergamo.

Guido da Landiano, Milan's Podestà, was made rector of the League, while the commander in chief would be none other than the bold Anselmo da Dovara. The legend mentioned at the top of my post would have it that the League of Bergamo and League of Verona would unite on April 7th 1167. Seeing as cities were still joining the league in May, the existence of the agreement has been discredited (D'Ilario 1976, Percivaldi 2009, Grillo 2010). However, the town of Pontida has been an enclave of the archdioceses of Milan inside the archdioceses of Bergamo since time immemorial. This proves nothing -I know- but it's a sufficiently weird coincidence that I'm not sure I'd question the existence a meeting at Pontida.

As part of the agreement, the contingent belonging to the western cities would be commanded by Anselmo da Dovara, while the eastern armies would be commanded by Ezzelino da Romano. Arms and armor would be heavily subsidized by Venice. Just as the league got in their battle-set against Emperor Frederick when the campaigning season started, the Emperor would rush back to Germany, going so far as taking a longer route to avoid confrontation with the humble city of Susa.

Edit: Verb tenses in disagreement.