of Northern Italy. Frederick also lost the military support of the German princes, who, after the 10,000 knights provided at the beginning of his campaign and the 3,000 laboriously collected shortly before the battle of Legnano, would hardly have given Barbarossa more aid to resolve the situation in Italy, which would have brought them very little benefit. Having no support at home, Frederick, to try to resolve the dispute, tried the diplomatic approach, with the armistice that was signed at the Venice congress of 1177. In this agreement, the emperor recognized, among other things, Alexander III as a legitimate pontiff and submitted to papal power by recomposing the schism that had arisen some years before. From then on, Beatrice I, Countess of Burgundy wife of Frederick ceased to be referred as Imperatrix ('empress') in the chancery productions, as her coronation as such had been made by an anti-pope and was thus declared nullified. The first negotiations for definitive peace took place in Piacenza between March and May 1183. The Lombard League asked Frederick Barbarossa the complete autonomy of the cities, the possibility of the latter to freely erect walls and fortifications, the exemption from all types of taxes and the absence of any kind of interference by the emperor in local matters; requests to which Frederick Barbarossa, in the first instance, firmly opposed. Shortly before the negotiations in Piacenza, from an imperial perspective, however, an important event occurred: Alessandria submitted to the imperial power and was recognized by Frederick as a city of the Empire. The continuation of negotiations led to the signing of the Peace of Constance (25 June 1183), which first of all provided for the recognition of the Lombard League by Frederick Barbarossa. As regards the individual cities, the emperor made administrative, political and judicial concessions; in particular, Frederick granted a wide autonomy with respect to the management of land resources such as forests, water and mills, with respect to court cases and related penalties and, finally, with regard to military aspects, such as the recruitment of army and the free construction of defensive walls and castles. As far as legal proceedings were concerned, the imperial vicars would have intervened in disputes only for the appeal cases that involved goods or compensation worth more than 25 lire, but applying the laws in force in the individual municipalities. Moreover, Barbarossa confirmed the customary law that the cities had