The First Vatican Council was a Catholic ecumenical council summoned by Pope Pius IX in 1868 and held from December 1869 to September 1870. It was the first ecumenical council held for over 300 years since the Council of Trent in 1545-63. Almost 750 churchmen from all parts of the Catholic world participated in the sessions. The Council was interrupted when military forces from the recently-united Kingdom of Italy occupied Rome after the fall of the French Second Empire, which had until that time acted as protectors of the Papal States.