Columbia subject headings:
Christian pilgrims and pilgrimages--Italy--Piacenza--Congresses.
Piacenza (Italy)--Church history--Congresses.
Piacenza (Italy)--History--Congresses.
Strada di Francia (Italy and France)
Harvard subject headings:
Christian pilgrims and pilgrimages--Italy--Congresses.
Christian pilgrims and pilgrimages--Italy--Piacenza--Congresses.
Piacenza (Italy)--Church history--Congresses.
Piacenza (Italy)--History--Congresses.
Strada di Francia (Italy and France)--History--Congresses.
Stradi di Francia (Italy and France)--Congresses.
Princeton subject headings: