Alright, so the timeline of Code Geass doesn't make sense at all. The Code Geass wiki has all the major events and their dates listed, and they all come from various sources from certain creators of the Code Geass anime, LN's, manga, games, etc.
However, even these creators don't know what they're talking about.
For example, the anime shows that right before the Battle of Narita, it began snowing, but how can the Battle of Narita take place on August 27 when it is next to impossible for snow to begin that early in an island nation, even in the mountains. The earliest they might receive snow in the mountains is probably late September.
Another thing is that in one of the Akito The Exiled films, Leila's journal says that it is May of 2017, but that is also impossible because those movies take place after R1 but before R2.
Lastly, the wiki states that R1 takes place over the course of only one month from August 2017-September 2017. This is completely and utterly unrealistic. Someone must've been taking some serious drugs to come up with this.
Study history. No war as big as the Black Rebellion would ever last so short.
For these reasons, I am going to list a timeline of the major canon events from 2017 onwards that cover R1, Akito The Exiled, and R2.
Here's the canon timeline list, but with much more realistic dates and a few additions by myself (some of these still need dates, especially Akito events, so I'll add those after rewatching the movies and may make changes as I go along):
R1 Timeline:
Year 2017 a.t.b.
May 6th: Emperor Charles zi Britannia appoints Second Princess Cornelia li Britannia the rank of Chief General of the Imperial Army and orders her to invade the Middle Eastern Federation.
May 8th: Under the new Chief General's command, Britannia invades the Middle East. Cornelia li Britannia begins a three-month-long military campaign and earns the title "The Goddess of Victory" when she conquers thousands of miles of land, being stopped short of only Saudi Arabia and Yemen by intense resistance.
May 27th: Naoto Kouzuki acquires intel from a Britannian mole that Prince Clovis is in possession of poison gas. Fearing that he plans to unleash it on his people, Naoto begins making plans to steal it, sharing the intel with the JLF and subsequently making the Kouzuki group popular amongst the other resistances.
June 29th: Naoto Kouzuki is killed while helping his group get away with the now stolen poison gas. The Shinjuku Ghetto is destroyed. Area 11's Viceroy and Third Prince Clovis la Britannia is killed by Zero.
July 2nd: Seeing that Charles zi Britannia hasn't done even considered who the new leader of Area 11 should be, Second Prince Schneizel el Britannia appoints Margrave Jeremiah Gottwald, leader of the Purist Faction, as the new Acting Viceroy until the Emperor can come to a decision and appoint a permanent one.
July 7th: Suzaku Kururugi is framed for Clovis' murder.
July 20th: Zero rescues Suzaku Kururugi.
July 23rd-July 25th: Suzaku Kururugi's trial. The judge, jury, and prosecution intended to drag it out, but as Lloyd Asplund and Cecile Croomy of the ASEEC are employees of Schneizel, the Prince, upon hearing their pleas and Suzaku's testimony, pardons the Honorary Britannian.
July 26th: Schneizel visits Suzaku, apologizes for the way he was treated, and has him treated in a military hospital and given a decent meal. However, he mainly visits to ascertain from Lloyd if the boy is the best pilot for the Lancelot.
August 3rd: Suzaku is finally released from the military hospital and given two days of leave, in which he meets Third Princess Euphemia li Britannia. Lelouch meets C.C for the first time since Shinjuku.
August 4th: The Middle East Federation is conquered by Cornelia, now renamed Area 18. Suzaku Kururugi transfers to Ashford Academy, facing an unpleasant welcome from most.
August 5th: Cornelia impatiently returns to Pendragon and requests to deploy to Area 11, eager to find Zero to avenge Clovis. Arthur the cat nearly sabotages Lelouch's identity as Zero.
August 7th: Emperor Charles delivers an infamous speech during Prince Clovis' funeral, one that receives tens of millions of dislikes on social media.
August 8th: After many stressful weeks of waiting on the Emperor for Schneizel, Second Princess Cornelia li Britannia is appointed Viceroy of Area 11, naming Third Princess Euphemia li Britannia as sub-Viceroy. As soon as she arrives in Area 11 that morning, Cornelia immediately begins her campaign to bring Zero to justice and attacks the Saitama ghetto to lure him out but fails. A frustrated Lelouch foreshadows to C.C his early plans for the USJ.
August 10th: Lieutenant Colonel Kusakabe of the JLF takes hostages at Lake Kawaguchi. Seeing this, Lelouch uses Ohgi's group to rescue the hostages. To directly challenge the Emperor, Zero, on the anniversary of the war, forms the Order of the Black Knights, the second fully organized resistance to Britannia's rule after the JLF was formed when Japan first fell. Zero proclaims that they will be the knights for justice of the world, and his bold speech is the first news-related video to reach 100 million + views and just as many likes on social media.
August 11th: The Black Knights are branded the most wanted terrorist organization by Viceroy Cornelia, despite not committing acts of terrorism.
For the remainder of the month, the Black Knights lay low to avoid Cornelia's wrath.
August 31st: The Japanese feel that they replaced one tyrant for an even worse one in Cornelia, going by her destruction of the Saitama ghetto. This month, in commemoration of the invasion, is always the most violent in terrorism, but news agencies report that August of 2017 marks the deadliest 31 day period in Area 11's history thus far.
Wave after wave of suicide bombers and car bombers attempt to breach the Viceroy's palace, but to no avail.
September 6th: The Black Knights begin a night-time war on the drug Refrain, which is popular amongst the Japanese in the ghettos.
September 18th: Guren ace Kallen Kouzuki, younger sister of Naoto Kouzuki, discovers her biological mother amongst the refrain addicts. She vows to make society better for her.
Meanwhile, Lelouch begins making plans to ambush Cornelia.
September 30th: The Battle of Narita. Long time fugitive Lieutenant Colonel Kyoshiro Tohdoh of the JLF is captured by Britannia.
October 1st: Zero comes to a secretive agreement with the Six Houses of Kyoto.
October 13th: The Battle of Port Yokosuka.
October 16th: Lelouch's first encounter with Mao, who manipulates Shirley.
October 20th: Lelouch uses his Geass on the Britannian Police to dispose of Mao, thinking him to be dead.
October 31st: Mao returns and kidnaps Nunnally, but Lelouch outsmarts him with Suzaku's help. C.C kills Mao, but not before he reveals something horrifying.
November 18th: Sentenced to execution, Kyoshiro Tohdoh is rescued by Zero and recruited for the Black Knights. Princess Euphemia chooses Suzaku Kururugi as her Knight of Honor.
November 25th: Suzaku Kururugi's ceremony to be knighted by Euphemia.
November 26th: The Ashford Academy Student Council throws a congratulatory party for Suzaku Kururugi's knighting.
November 27th: The Battle of Shikinejima. Lelouch uses his Geass to order Suzaku to live.
November 28th: Zero and Kallen steal the prototype knightmare Gawain. The remnants of the Japanese government collaborate with the Chinese Federation to begin the Battle of Kyushu, launching a full-scale assault.
November 29th: Princess Euphemia announces her plans to create the Special Administrative Zone of Japan, or SAZ for short.
December 2nd: The planned inaugural ceremony to open the SAZ goes south when Euphemia orders the Elevens to be slaughtered. Zero uses this opportunity to kill Euphemia and incite a nationwide uprising, as well as the inception of Area 11's name when they overthrow their oppressors: The United States of Japan (USJ for short).
That night, he delivers Viceroy Cornelia an ultimatum. Surrender at exactly 12:00, midnight, and not one second later as his forces begin converging towards Tokyo for the First Battle of Tokyo Settlement.
December 3rd- The Black Rebellion breaks out. Riots ignite across the country as the Black Knights continue to push towards the Area 11 Viceroy Palace. The rebellion is eventually pushed back and crushed, with most of the Black Knights killed or captured. Area 11 is demoted to a correctional sub-area.
Second Princess Cornelia li Britannia goes missing during the Black Rebellion. Her position as Viceroy of Area 11 later is taken by Duke Calares.
The Black Knights still at large, and those that supported Zero, go into hiding.
Most notably, in the waning hours of the battle, the masked vigilante, Zero, Britannia's most wanted terrorist, was nowhere to be found.
.
.
.
.
.
.
.
Akito The Exiled Timeline:
December 4th: Inspired by Zero, rebellion spreads across the empire. Glinda Knights and the Knights of the Round are dispatched to certain Areas to maintain control.
December 5th: It is Lelouch vi Britannia's 18th birthday, or at least it was supposed to be. However, very few know where he is.
December 6th: E.U Army's 132nd Regiment encircled at Narva on the way to liberate Saint Petersburg from Euro-Britannia. The W-0 Unit successfully breaks encirclement at the cost of all the knightmare pilots' lives except Captain Akito Hyuga.
December 7th: Shin Hyuga Shaing murders Michele Manfredi and is accepted as the next Grand Master of the Holy Order of Michael.
December 11th: The W-0 and the Holy Order of Michael clash in Slonim, Belarus.
December 17th: A mysterious man named Julius Kingsley is sent by the Emperor of Britannia alongside Suzaku Kururugi, the Knight of Seven, to take command of all Eurasia operations.
.
.
.
Some parts I still need to put in dates are from this point onwards:
Julius Kingsley enacts ARC Fleet plan to incite mass chaos in Europe while Euro Britannia invades. Grand Duke Augusta Henry Velaines refuses, citing mass casualties among civilians. Kingsley has Velaines arrested for questioning his orders.
Shin Hyuga Shaing undertakes a coup d'etat of Euro Britannia. Julius Kingsley and Suzaku Kururugi are jailed, Grand Masters Gaudefroy du Villon and Raymond du Saint-Gilles are beheaded, and Euro Britannia grants Shin emergancy powers in order to combat the E.U and Britannia.
Julius Kingsley and Suzaku Kururugi are released by Geass Order agents led by a mysterious person named Rolo.
It is around this time that Julius Kingsley disappeared. Coincidentally, Lelouch Lamperouge returns to Ashford Academy.
.
.
.
.
.
.
R2 Timeline
Year 2018 a.t.b.
May 18th: The remaining members of the Black Knights incite riots in Babel Tower which kill Calares.
Within the Chinese Federation Consulate of Area 11, Zero reappears and redeclares the United States of Japan.
Europia United is losing to Britannia leading to more colonization of its countries to areas
The former Knight of Princess Cornelia, Gilbert G. P. Guilford, declares himself as new Viceroy. He then announces to execute Black Knights' members, although it's failed thanks to Zero's crafty strategy.
June 14th: Princess Nunnally vi Britannia becomes Viceroy of Area 11.
Nunnally attempts to reestablish the Special Administration Zone of Japan. Zero gives his support on the condition that he be exiled. Zero, along with over a million of his supporters dressed like him, are exiled from Area 11 and seek asylum on Penglai Island located within the political borders of the Chinese Federation. Because all of Zero's supporters were the participants in the zone, the attempt ends in failure.
June 30th: Li Xingke and Zero disrupt the arranged political wedding between First Prince Odysseus eu Britannia and Empress Tianzi of the Chinese Federation.
July 12th: The High Eunuchs are summarily executed for lèse majesté against the Empress. An alliance between the Black Knights and the Chinese Federation is forged.
July 13th-18th: After the fragmentation of the Chinese Federation, Second Prince Schneizel el Britannia prepares to annex many of its territories through a combination of diplomatic means, which results in failure.
July 22nd: Europia United is finally conquered after being at war with Britannia for exactly 77 years and 1 month since June 22nd, 1941, coincidentally the same day that Adolf Hitler invaded the Soviet Union
August 10th: Ratification of the United Federation of Nations is completed, with the Order of the Black Knights to serve as its chief military branch. Its first resolution is to take action against the occupying Britannian forces in Japan, which leads to a declaration of war between the UFN and the Holy Britannian Empire.
August 15th-16th: The UFN initiates the Second Battle of Tokyo to reclaim Area 11. The first use of the FLEIJA by the Britannians results in massive damages to the concession area of the Tokyo Settlement.
August 18th: Zero is reported to be killed during the Second Battle of Tokyo. However, there are rumors that this is falsified information for reasons unknown. In light of the alleged death of Zero, a truce is negotiated between the UFN and Britannia, with a peace treaty being drafted. The treaty results in the neutrality of Japan.
August 19th: A coup d'etat is enacted by Second Prince Schneizel and the Knight of Seven, Suzaku Kururugi. Meanwhile, Lelouch vi Britannia instigates his own rebellion, forcing his followers to his will with the power of Geass.
98th Emperor Charles zi Britannia is killed by Lelouch, the former 11th Prince.
September 22nd: One month after the Second Battle of Tokyo, Lelouch vi Britannia coronates himself as the 99th Emperor of the Holy Britannian Empire and appoints the title of "Knight of Zero" to Suzaku Kururugi. With his ascension come many changes in Britannian policies, including the destruction of the Imperial Mausoleum and the abolishment of privileges to nobles. This leads to many attempts of rebellion (one of which is led by the Knight of One, Bismarck Waldstein), each of them futile against Britannia's new and more ruthless leader.
October 1st: Britannia attempts to join the UFN, and negotiation takes place in Japan, now a neutral zone. However, the leaders of the UFN and the Black Knights attempt to convince Emperor Lelouch to lower Britannia's voting rights as a balance for the UFN. The attempt fails, and in response Britannia launches an invasion against Japan, capturing the leadership of the UFN.
October 2nd: FLEIJA is used on the Britannian capital of Pendragon from the Aerial Fortress Damocles, created by the Toromo institute, by former Second Prince Schneizel, resulting in the complete decimation of the capital.
Two weeks of preparation are done by both sides as they plan for the battle that would decide the fate of the world.
October 17th-18th: The Battle of Mount Fuji begins, also known as the Battle for Earth. Both sides suffer heavy losses, but eventually Emperor Lelouch is able to take control of Damocles and ends the battle, as well as the war between Britannia and the UFN, with a display of power from the Damocles.
Emperor Lelouch vi Britannia declares himself ruler of the world, being the first and only person to ever conquer the entire planet to date. All resistance has died as the world is in a state of total shock and fear of speaking out.
December 2nd: Two months later, during a supervision of executions of the Black Knights and UFN leaders, Suzaku Kururugi masquerades as Zero and assassinates Lelouch to complete the Zero Requiem.
December 6th: Nunnally vi Britannia succeeds her elder brother as the 100th Empress of Britannia and begins to work in cooperation with the UFN to achieve peace.