Editing Papal States (section)

===Italian invasion of Rome, 1870===
{{Main|Capture of Rome}}
[[File:I bersaglieri alla presa di Porta Pia. Autore Michelle Cammarano.jpg|thumb|The breach of Porta Pia during the [[Capture of Rome]]]]

The opportunity for the Kingdom of Italy to eliminate the Papal States came in 1870; the outbreak of the [[Franco-Prussian War]] in July prompted Napoleon III to recall his garrison from Rome and the collapse of the [[Second French Empire]] at the [[Battle of Sedan]] deprived Rome of its French protector.

King [[Victor Emmanuel II]] at first aimed at a peaceful conquest of the city and proposed sending troops into Rome, under the guise of offering protection to the Pope. When the Pope refused, Italy declared war on 10 September 1870, and the [[Royal Italian Army]], commanded by General [[Raffaele Cadorna]], crossed the frontier of the Papal territory on September 11 and advanced slowly toward Rome.

The Italian Army reached the [[Aurelian Walls]] on September 19 and placed Rome under a state of siege. Although the Pope's tiny army was incapable of defending the city, Pius IX ordered it to put up more than token resistance to emphasize that Italy was acquiring Rome by force and not consent. This incidentally served the purposes of the Italian State and gave rise to the myth of the [[Capture of Rome#Breach of Porta Pia|Breach of Porta Pia]], in reality, a tame affair involving a cannonade at close range that demolished a 1600-year-old wall in poor repair. The defence of Rome was not however bloodless, with 12 dead and 47 wounded amongst the Papal forces and 32 dead plus 145 wounded of the Italian troops.<ref>{{cite book |first=David |last=Alvarez |page=248 |title=The Pope's Soldiers |date= 2011 |publisher=University Press of Kansas |isbn=978-0-7006-1770-8}}</ref>

Pope Pius IX ordered the commander of the Papal forces to limit the defence of the city in order to avoid bloodshed.<ref>{{cite web |url=http://www.guardiasvizzera.va/content/guardiasvizzera/en/storia/1870-fine-dello-stato-pontificio.html |title=History of the Pontifical Swiss Guard |access-date=30 August 2016 |archive-date=3 February 2019 |archive-url=https://web.archive.org/web/20190203143600/http://www.guardiasvizzera.va/content/guardiasvizzera/en/storia/1870-fine-dello-stato-pontificio.html |url-status=dead}}</ref> The [[Capture of Rome|city was captured]] on 20 September 1870. Rome and what was left of the Papal States were annexed to the Kingdom of Italy as a result of a [[plebiscite]] the following October. This marked the definitive end of the Papal States.{{sfn|Hanson|2015|page=252}}

Despite the fact that the traditionally Catholic powers did not come to the Pope's aid, the papacy rejected the 1871 "[[Law of Guarantees]]" and any substantial accommodation with the Italian kingdom, especially any proposal which required the Pope to become an Italian subject. Instead, the papacy confined itself (see [[Prisoner in the Vatican]]) to the [[Apostolic Palace]] and adjacent buildings in the loop of the ancient fortifications known as the [[Leonine City]], on [[Vatican Hill]]. From there it maintained a number of features pertaining to sovereignty, such as diplomatic relations since in canon law these were inherent in the papacy.

In the 1920s, the papacy – then under [[Pius XI]] – renounced the bulk of the Papal States. The [[Lateran Treaty]] with [[Fascist Italy|Italy]] (then ruled by the [[National Fascist Party]] under [[Benito Mussolini]]{{sfn|De Grand|2004|page=89}}) was signed on 11 February 1929,{{sfn|De Grand|2004|page=89}} creating the [[State of the Vatican City]], forming the sovereign territory of the [[Holy See]], which was also indemnified to some degree for loss of territory.