On the 30th of April 1183, the ambassadors of the emperor Federico Barbarossa with Lega Lombarda’s deputies came togheter in Piacenza. Six years had passed from the Legnano’s battle (1176); from that stunning and unexpected loss for the emperor, the meeting was organised by the municipalities, who had sworn for the Lega Lombarda in Pontida (1167).
Under the pronaos of Sant’Antonino church the representatives of the two sides, decided to sign the procedure which contained the rules for the peace. The peace was officially sealed in Costance during the same year.
In 1876, after seven Ceturies, a marble plaque was placed under that pronao, which is still today visible, to remember that important event.
The inscription says: ” In this temple, on the 30th April and the 1st of May 1183, the Lega Lombarda won on Barbarossa with the Legnano battle, promising the peace, set off later in Costance. Glory to the ancestors, great example to the future generations, 700 year from the win. 29th of May 1876″.
The basilica was the ancient episcopal seat of Piacenza, the cathedral was moved inside of the walls from 855 d.C.
The architectonical structure of Sant’Antonino church is telling a long story.
The first building was developed on the guideline east and west, the transept was added only later. In 1350, the “Portico del Paradiso”(porch of paradise) was built and it turned to be the main entrance of the church, along the way of the pilgrims passage. The porch was the place that hosted the meeting between the emperor and the deputies.
The architectonical project was signed by Pietro Vago, the same architect who built the bell tower of the current Cathedral of Piacenza.
The peace: documents and negotiations
In 1162 the city of Piacenza signed an agreement with the Emperor Frederick Barbarossa, which witnesses the long negotiations among the sides. The agreement included tough condition for Piacenza: the downing of the city walls, the admission of an imperial podestà and some exceptional payments.
The official document of the Costance Peace is included inside of the Registrum Magnum of the Piacenza “Archivio di Stato”.