1157 Establishment of the Bank of Venice.
1158 Milan again destroys Lodi. Second appearance of Frederick in Italy. Siege of Milan, which surrenders on account of famine. Diet at Roncaglia. The Bolognese jurists expound the code of Justinian to Frederick, who removes the consuls and substitutes the podesta as ruling officer in the Italian cities.
1159 The Milanese refuse to obey the podesta.
1160 Surrender of Crema to Frederick. The city is abandoned to the cruelty of Cremona. Lucca obtains its independence from Welf of Tuscany.
1162 Surrender of Milan after a nine months’ siege. It is totally destroyed. Lombardy submits to Frederick.
1163 The cities of the Veronese March, assisted by Venice, form a league against Frederick.
1167 Siege of Ancona by Frederick, who has returned to Italy the previous year. Brescia, Bergamo, Mantua, Verona, Cremona, Treviso, and other north Italian cities form the Lombard League to regain their liberties from Frederick. It begins to rebuild Milan.
1168 Frederick, with his army nearly annihilated by the plague, returns to Germany.
1169 The league builds Alessandria. The pope and Eastern emperor join the league against Frederick. Other cities enter the league. Pavia and Montferrat alone remain loyal to the empire.