St. Peter's Basilica

St. Peter's Basilica (聖ピエトロ大聖堂) is a basilica of the Roman Catholic Church. Found in the Vatican, it is the world's largest cathedral. and the greatest Roman Catholic stronghold. It is later completely destroyed by Fiamma of the Right in mid-October of the current year of the timeline.

History
Although there are many turning points in the history of the basilica the first turning point was St. Peter’s death and the building of his tomb. The basilica was established upon St. Peter's tomb, where the Croce di Pietro was set-up on the June the 29th. From then on, the location where the cross stood and several square kilometers of land and the denizens within, became the dominion of the Roman Catholic Church.

With regards to the creation of the church, since the view of the Roman Catholics is that since the place where Peter is buried, then it should not be disturbed. As such, they must do their best to maintain his heritage. Emperor Constatine paid his respects towards the Saint, and had ordered the construction of the church that is now known as the Old St. Peter's Basilica in the 4th century. During the Renaissance there was a pleasant large scale reformation of the church, to which the Old St. Peter's Basilica was replaced by the current form of the basilica, with the aid of the architectural masters of that time such as Michelangelo.

As such, the basilica became known as the largest Church in the heart of Roman Catholicism, the largest religion in the world, becoming an icon of the Vatican.

Recent history
Sometime before the start of the series, the church became the stronghold and base of operations of the enigmatic God's Right Seat. Moreover, Index was also sent into the basilica when visiting Vatican, the other being in the Vatican Library, most likely to read the grimoires there.

Destruction of St. Peter's Basilica
During the height of the prewar tensions between the Anglican Church and the Roman Catholic Church, Matthai Reese entertained negotiators from the Anglican Church. He later dismess them after hearing of Acqua of the Back's defeat, giving a severe blow to the Church's fighting strength and had allowed its enemies to assume superior fighting strength for themselves. As the Pope concludes that Kamijou Touma is truly a dangerous opponent, Fiamma of the Right appears before him, implying to him that the Pope hoped for Acqua of the Back's defeat and mocking the Roman Catholic Church for erasing all traces of it stirring trouble. Fiamma of the Right then criticizes the Pope's leadership in the midst of crisis, specifically in the defeat of Acqua of the Back, prompting the Pope to ask what he is going to do now that all of the rest of the God's Right Seat have failed, telling him that a plan to crush Academy City is needed.

Betraying the Pope's expectations, Fiamma of the Right says that they must bring England down to its knees, pointing out that with their alliance with the Russian Orhodox Church, all of Europe is in their grasp, giving the means of crushing England. The Pope doesn't understand, to which Fiamma of the Right points out that since they are allied, if England were to come under attack, it would deal a severe blow to Academy City as it would be unable to continue the war. The Pope however says that conversely, if the war were to fall on Academy City first, England's actions would be halted as going to war with the other great denominations of Christianity would be unthinkable.

Fiamma of the Right retorts that his target isn't Academy City, but something which in England and that the Church must focus all of its attention on England instead. The Pope doesn't understand what Fiamma of the Right saying. He states that his actions is not entirely out of the Pope's wishes as if he acquired that thing in England, he can utterly shatter the entire science side. The Pope tries to ask what the "thing" Fiamma of the Right is referring to, Fiamma of the Right instead slams two columns of the basilica down upon him. Shocked, the Pope asks if Fiamma of the Right is truly of Christianity. Here, Fiamma of the Right reveals that he's been using him all along. Knowing that Fiamma of the Right's isolation of England would surely cause a war in Europe, the Pope tries to contend against Fiamma of the Right, though he is unperturbed by the Pope's threats. With that, the Pope used magic based on the suffering of Judas after his betrayal of Jesus Christ to trap Fiamma of the Right in 40 years of despondency. In spite of the Church's billions of followers and thousand years of history, Fiamma of the Right uses his own power to easily destroy the Pope's magic and destroy part of the walls that surround the Vatican and severely weakens the defensive array that surrounds the city.

The attack sends the Pope flying one-hundred meters though he survives. Fiamma of the Right reveals to the Pope his power, the Holy Right. However, Fiamma of the Right reveals that though the Holy Right possess immeasurable power he is still human, and that he is unable to utilize its full potential. Fiamma of the Right asks the Pope if his Holy Right is what he wanted, as it is the Right Hand that creates all miracles and destroys all evil, and asks if he isn't curious what would happen if masters the Holy Right, though he needs materials to master it. Then the Pope realizes something, Fiamma of the Right may be after the Imagine Breaker, the Right Hand that destroys all miracles if touched. Moreover, he realizes that even if he had gathered the materials to master the Holy Right, he needed the knowledge to create the spell, and the only way for him to do that is to get the Index Librorum Prohibitorum. The Pope realized that Fiamma of the Right is targeting England in order to draw Index back there. The Pope tries to charge Fiamma of the Right again anew but almost instantly is blown away by his overwhelming attack, enough to destroy the rest of the basilica, and even destroy a part of the perimeter wall separating the Vatican from the Rome.

Vatican soldiers finally respond and attacks Fiamma of the Right, though are completely defeated as well. Fiamma of the Right however realizes that the damage to the rest of the Vatican was too minimal and finds out that the Pope manages to divert the spell onto himself to save the city, impressing him. FIamma of the Right later leaves, not hiding that he was the one that caused the destruction.

Aftermath
The Pope later regains consciousness and is content with the fact that there were no casualties. The Pope later sees a dirty street urchin girl, likely the same one from after his recent speech Basilica of Sant'Agostino, worrying about him. Vento of the Front later arrives to comment on the destruction, and calls back to their conversation after the failed use of the La Regina del Mare Adriatico, asking him if he still hates to be voted by the people after saving the lost sheep. The Pope tries to tell Vento of the Front to go to England where Fiamma of the Right is going, to which Vento of the Front says not to command her, though says that since Fiamma of the Right's goal is to kill everyone she'll just let it be. Vento of the Front then notices the street urchin glaring at her, and praises her hostility, though states tha she is lucky as if she had her original weapon, she would've died. Vento of the Front later leaves, and medical personnel later take care of the Pope.

News spread fast, as Archbishop Laura Stuart receives reports of the attack while relaxing in a boat in Little Venice, London. The report says that there has been in-fighting within the Roman Catholic Church, and that the Pope has been injured though unknown if he is alive or dead. The reporter says that the damage should've been greater, in which Laura Stuart immediately determines as to the reason why—there was an ordinary behind where the Pope was found, and as such he protected it from the magic attack.

Principles
Since the Vatican's defensive power is directly related to the amount of relics that have significance to Christianity, the basilica is the greatest stronghold of Roman Catholicism, as such destroying even a small part of it, like a pillar, might cause problems with its defensive functionality.

The Pope, is empowered by the 2 billion followers and the 2,000 years history of the Church. The basilica, being the largest and highest stronghold of Roman Catholicism, and being one of the most significant symbols of Christianity, and combined with the other parts of the Vatican, adds to the power of the Pope, like a powerful spiritual item.

Interior
The interior of the basilica is where most meetings between the Pope and the members of God's Right Seat occur. Moreover, deep within the bowels of the church is where Fiamma of the Right had apparently spent most of his time before his introduction. Furthermore, below the basilica is the vast library where Index was once guided to.

The tomb of St. Peter is supposedly located within the confines of the basilica.