Construction of the Old St. Peter's Basilica began on orders of Roman Emperor Constantine I between 318 and 322. It took around 40 years to complete and over the centuries, it became a significant pilgrimage site in Rome before being destroyed by fire.

Emperor Constantine I began constructing a basilica over St. Peter's tomb in 324, which later became the spiritual center for Christian pilgrims.

After the fall of the Roman Empire in 476, the Vatican Hill became the residence for the popes, marking a significant shift in the history of the Vatican.

In 754, donations from Pepin the Short played a crucial role in creating the Papal States, enhancing the power and land holdings of the pope.

In the year 800, Charlemagne, the King of the Franks, acted as a judge in the case of Pope Leo III against charges of perjury and adultery. This event marked a significant moment in the history of the Vatican City.

Charlemagne presides over the trial of Pope Leo III in the Vatican, assessing the accusations brought against him.

In 846, Saracen pirates attacked and looted St. Peter's Basilica in Rome, causing significant damage to the structure and stealing valuable items. This event led to the construction of defensive walls around the basilica by Pope Leo IV.

Following the Treaty of Venice in 1177, the Papal States gained independence from the Holy Roman Empire, reshaping the political landscape of the Vatican.

In 1279, Pope Nicholas III enclosed the area to the north of the Papal Apostolic Palace with walls and planted an orchard, a lawn, and a garden.

In 1309, the Papal court moved to Avignon, France due to a disagreement that arose after French king Philip IV elected a French pope, Clement V, in 1305. This move led to a period of abandonment in Rome.

Pope Gregory XI moved the Papal court back to Rome in 1376 after years of abandonment in Avignon. The move back to Rome marked a significant return for the Papal court.

In 1440, it was revealed that the claim of Pope Sylvester having sovereignty over the Eastern Church and Imperial Power over the West was a fabrication, impacting the legitimacy of the Roman Catholic Church and the Vatican.

The Sistine Chapel is officially opened in the Vatican, showcasing its renowned frescoes and artwork.

The Pontifical Swiss Guard was founded by Pope Julius II on 22 January 1506 as the Pope's personal bodyguard. It is responsible for the personal security of the Pope and residents in the Vatican City State.

Pope Julius II lays the foundation stone for the present St. Peter's Basilica in the Vatican, initiating the construction of the iconic church.

Pope Julius II commissioned Michelangelo to paint the Sistine Chapel ceiling in 1508, leading to the creation of one of the most famous artworks in history.

In 1512, Michelangelo's iconic paintings on the ceiling of the Sistine Chapel in the Vatican were first exhibited to the public, showcasing his exceptional talent as a sculptor and painter.

Pope Julius II died in 1513, during the early stages of the construction of the new Saint Peter's Basilica.

On May 6, 1527, troops loyal to Charles V, Holy Roman Emperor, mutinied over unpaid wages and nearly razed Rome to the ground, in a savage and vicious attack.

On October 31, 1541, Michelangelo Buonarroti completed the painting 'The Last Judgement' in the Sistine Chapel, Vatican City, a masterpiece that is renowned for its depiction of the final judgment day.

In 1578, Étienne Dupérac created a bronze engraving depicting a Mass in the Magna Chapel in the Vatican.

In 1586, the Vatican obelisk was relocated to its current position in St. Peter's Square by Pope Sixtus V using a method devised by Italian architect Domenico Fontana. The obelisk was originally brought from Heliopolis in Egypt by Emperor Caligula.

In 1593, the Vatican initiated a trial for blasphemy and theological heresy against Italian scholar Giordano Bruno, which lasted for over 7 years. Bruno, a wayward friar, faced accusations related to his unorthodox beliefs and teachings.

In 1600, the Vatican convicted scholar and friar Giordano Bruno of heresy for refusing to recant his beliefs. He was turned over to civil authorities and sentenced to death.

In 1626, St. Peter's Basilica, the largest church in the world, was built.

The Vatican Museums, originating from the sculpture collection of Pope Julius II, opened its earliest gallery to the public in 1773, showcasing a vast array of artistic treasures.

Napoleon's troops entered Rome on 6th February 1798, leading to significant changes in the power dynamics and control over the Papal States.

The 20th Roman Catholic ecumenical council, Vatican I, commences in Rome.

Pope Pius IX and the First Vatican Council officially declare the concept of papal infallibility.

On September 20, 1870, the king's army forcibly occupied Rome after annexing pieces of the Papal States, leaving only the Vatican within its walls.

France recalls its ambassador to the Vatican in protest of the Pope's disciplinary actions towards French bishops, further straining the relationship between France and the Catholic Church.

Joan of Arc is beatified by the Roman Catholic Church at St. Peter's Basilica in the Vatican.

The Vatican includes the works of Belgian Nobel laureate Maeterlinck in its index of forbidden books.

Latvia and the Vatican reach an agreement through a formal accord.

Benito Mussolini requests the Vatican's endorsement for his fascist party program.

Bavaria and the Vatican come to an agreement through an accord.

The Vatican adds the work of French fascist Charles Maurras to its list of prohibited books.

In 1929, the Lateran Treaty was signed between the Vatican City and Italy, establishing the Vatican City as a sovereign state. This agreement resolved the long-standing Roman Question, granting the Pope temporal authority over the Vatican City.

The Lateran Treaty established the independent state of the Vatican City, granted Roman Catholicism special status in Italy, and made Vatican City the smallest nation in the world. It was signed by Benito Mussolini, and Italy recognized papal sovereignty over the Vatican City.

The Vatican City started operating its postal system on February 13, 1929, and began releasing its own postal stamps under the authority of the Philatelic and Numismatic Office of the Vatican City State.

In 1929, Vatican City officially became a sovereign state.

In 1929, Prussia and the Vatican signed a Concordat.

In 1929, Mexico and the Vatican signed a Concordat.

In 1929, Romania and the Vatican signed a Concordat.

On August 1, 1929, Vatican City started releasing its own postal stamps under the authority of the Philatelic and Numismatic Office of the Vatican City State.

In 1930, the Vatican approved the rhythm method for birth control.

In 1931, Vatican Radio started broadcasting with the callsign HVJ.

On July 20, 1933, Vatican state secretary Pacelli, who later became Pope Pius XII, signed the Reichskonkordat accord with Adolf Hitler's Nazi Germany. This agreement established the relationship between the Vatican and the Nazi regime.

On May 1, 1934, Austria signed a pact with the Vatican. This agreement solidified the relationship between Austria and the Vatican.

On March 12, 1939, Pope Pius XII was crowned as the 260th Supreme Pontiff in a ceremony at the Vatican. This event marked the official ascension of Pius XII to the papacy.

The Corps of Firefighters of the Vatican City State was established in its present form in 1941. It is responsible for fire fighting and various civil defence scenarios in the Vatican City State.

On September 10, 1943, German troops occupied Rome and took over the protection of Vatican City. This event had significant implications for the security and autonomy of the Vatican.

In 1944, the Dutch initiated diplomatic communication with the Vatican in London.

After refraining from creating cardinals during World War II, Pope Pius XII announced his intention to create 32 cardinals in early 1946. This move aimed to fill prominent vacancies in key positions within the Vatican hierarchy.

On October 30, 1950, Pope Pius XII reportedly witnessed 'The Miracle of the Sun' while at the Vatican.

Since 1952, the President of the Pontifical Commission for Vatican City State has been the principal subordinate government official for Vatican City, exercising functions previously held by the Governor of Vatican City.

On July 27, 1953, the Vatican issued a decree prohibiting priests from working in factories during holidays.

The Vatican is the only site to date registered with the UNESCO as a centre containing monuments in the 'International Register of Cultural Property under Special Protection' according to the 1954 Hague Convention for the Protection of Cultural Property in the Event of Armed Conflict.

Pope John XXIII announced the convening of the 2nd Vatican Council on January 25, 1959.

In April 1959, the Vatican issued an edict prohibiting Roman Catholics from voting for communist parties.

On October 11, 1962, Pope John XXIII initiated the convening of the Second Vatican Council, the 21st ecumenical council of the Catholic Church.

On September 29, 1963, the 2nd session of the Ecumenical council known as Vatican II was opened in Rome by Pope Paul VI.

Pope Paul VI closed the second session of the 2nd Vatican Council on December 4, 1963.

The 3rd sitting of the 2nd Vatican Council opened in Rome on September 13, 1964.

Pope Paul VI signed the 3rd sitting of the 2nd Vatican Council on November 21, 1964.

On September 14, 1965, the 4th meeting of the 2nd Vatican Council was opened.

Pope Paul VI concludes the final session of the Second Vatican Council, a significant ecumenical council that brought about modernization in church practices.

The Apostolic Constitution of 1967 in Vatican City comes into effect, marking an important event in the governance of the city-state.

On March 28, 1968, Pope Paul VI abolished honorary positions such as Quartermaster general and Master of the Horse that had continued to exist within the Vatican City.

At the Second Vatican Council, the official revocation of the Edict of Expulsion of Jews from Spain takes place, signifying a significant historical moment.

By the will of Pope Paul VI, the Pontifical Military Corps, except for the Swiss Guard, was disbanded in September 1970. The Gendarmerie Corps was reorganized into a civilian police and security force.

Pope Paul VI hosts an audience with Israel Prime Minister Golda Meir at the Vatican, showcasing diplomatic relations between the Vatican and Israel.

The funeral of Pope Paul VI took place in the Vatican after his death, with his body lying in view.

Pope John Paul II welcomed Lech Wałęsa and a delegation from Solidarity at the Vatican.

Pope John Paul II was shot and critically wounded by Turkish gunman Mehemet Ali Agca in St Peter's Square, Vatican City.

A Spanish Traditionalist priest who opposed Vatican II reforms and viewed Pope John Paul II as a perpetrator of them, was stopped prior to his attempt to attack the Pope with a bayonet in Fatima, Portugal.

US President Ronald Reagan met with Pope John Paul II at Vatican City, Rome, and later with Queen Elizabeth II.

In 1984, the Vatican was added by UNESCO to the List of World Heritage Sites, being the only one to consist of an entire state.

The Vatican officially expressed its opposition to test-tube fertilization and embryo transfer.

In 1993, the Mafia carried out bombings targeting historical buildings in Rome, Milan, and Vatican City, resulting in the death of 5 individuals.

On December 30, 1993, the Vatican officially recognized Israel as a sovereign state.

The Vatican marked The Holocaust for the first time on April 7, 1994, by organizing an orchestral concert in the Sala Nervi.

In 1995, the construction of a new guest house, Domus Sanctae Marthae, adjacent to St Peter's Basilica faced criticism from Italian environmental groups and politicians. They argued that the new building would obstruct views of the Basilica from nearby Italian apartments, leading to tensions between the Vatican and the Italian government.

On December 23, 1997, a Channukah candle was officially lit in Vatican City for the first time, symbolizing the celebration of Hanukkah and efforts to reconcile Roman Catholics and Jews.

In 1998, a guard named Colonel Estermann was found shot dead in the Vatican. The bodies were discovered after a neighbor reported loud noises coming from the commander's apartment. Colonel Estermann had been protecting the Pope for 18 years.

Since 1999, the Vatican City has used the Euro as its currency, under a special agreement with the European Union. Vatican euro coins are highly sought by collectors due to their rarity.

Pope John Paul II installed 44 new cardinals at one time, the largest number ever installed. This brought his total appointments to 166, more than any other pope.

In 2002, Pope John Paul II held a meeting with U.S. Catholic Church leaders at the Vatican to address the issue of sexual abuse of minors within the Church.

In July 2007, the Vatican accepted a proposal to become the first carbon neutral state by offsetting its carbon dioxide emissions with the creation of a Vatican Climate Forest in Hungary. The initiative aimed to symbolically encourage Catholics to protect the environment.

On 26 November 2008, the Vatican implemented a plan to cover the roof of the Paul VI Audience Hall with solar panels. This initiative was part of a larger effort to promote sustainability and reduce carbon footprint.

In 2009, Vatican City experienced a decrease in its financial resources.

In 2011, Vatican City faced another decrease in its financial situation after a brief period of profit.

In 2012, Vatican City was listed among the nations of concern for money-laundering by the US Department of State's International Narcotics Control Strategy Report.

Pope Benedict XVI delivers his farewell speech to Vatican City before stepping down from his position as the 265th Pope.

Jorge Mario Bergoglio from Buenos Aires, Argentina, was elected as Pope Francis on March 13, 2013. He serves as the head of state of Vatican City and the spiritual leader of the Catholic Church.

Pope Francis establishes a new Secretariat with the authority to conduct audits on any Vatican agency at any given time.

Pope Francis issues a letter from the Vatican urging priests to forgive women who have undergone abortions.

In 2016, Mother Teresa was officially declared a saint by Pope Francis in a ceremony held at the Vatican.

US President Donald Trump had a meeting with Pope Francis at the Vatican in 2017.

In 2017, Vatican treasurer Cardinal George Pell faced charges of historic sexual offenses in Victoria, Australia.

The Vatican made an announcement in 2017 revealing the rediscovery of the last paintings of Raphael, dating back to 1520, in the Vatican Museum.

Pope Francis and the Vatican issue a statement expressing support for the 300 victims of 'predator priests' in Pennsylvania.

Archbishop Carlo Maria Vigano, former US Vatican Ambassador, accuses Pope Francis of knowing and disregarding sex abuse allegations against Cardinal Theodore McCarrick.

The Vatican confirms the existence of secret church guidelines regarding the children of priests.

Catholic Cardinal George Pell is found guilty of child sexual abuse in Melbourne, Australia. As the treasurer at the Vatican, he becomes the highest-ranking church official to be convicted; the conviction is later overturned in 2020.

Russian President Vladimir Putin had a meeting with Pope Francis at the Vatican.

A blog post discussing the history of the Vatican, covering its ancient roots, Middle Ages, Italian Renaissance, and modern age.

The Vatican issued a judgement stating that priests cannot bless same-sex unions, as they believe God does not bless sin.

Spanish Cardinal Fernando Vérgez Alzaga was appointed as the President of the Governorate of Vatican City on October 1, 2021.

On 28 June 2022, Vatican City recorded its highest temperature ever at 40.8 °C (105.4 °F). This extreme heat marked a significant weather event in the region.

The article provides a concise overview of the history of Vatican City, delving into its origins, significance, and key landmarks like Saint Peter's Basilica and the Sistine Chapel.

María Antonia de Paz y Figueroa, also known as Mama Antula, was canonized as Argentina's first female saint at a ceremony attended by President Javier Milei at the Vatican.