Papato Impero e regni occidentali Dal periodo carolingio a Innocenzo III - Frugoni, Arsenio 1914-1970 (Sansoni, 1940)
Keywords: Katholische Kirche; Catholic Church -- Foreign relations -- Holy Roman Empire; Geschichte 800-1200; Außenpolitik; Geschichte; Papacy -- History; Papst; Kaiser; Holy Roman Empire -- Foreign relations -- Catholic Church