The World Of Code Geass:
Now the whole 55 BC, High King Eowyn thing never happened and it is simply revisionist history by the Britannian government who like all fascist nations mythologise their history to their people. However the POD for this world was during the Elizabethan Age where Elizabeth I did take a lover and give birth to an illegitimate child. The desire to keep a Protestant king on the throne was what lead to Henry IX crowning after his mother's death. With a solidly Protestant dynasty on the English throne England managed to avoid the English civil War and kept the power of the monarch closer to absolute than OTL. The colonisation of the Americas also saw a greater proportion of landed gentry arriving at the behest of the Royal family who were able to gain large, prosperous estates and plantations in the New World.
Eventually an age of revolution began by the Enlightenment led to a Napoleon analogue emerging in France. The British were defeated and forced to flee to their colonies where a few years prior a republican revolution had broken out and was brutally put down. The influx of absolutists, aristocrats conservatives and loyalists ended any possibility of another rebellion taking place. However the British colonists rallied and attacked the weak and overstretched European colonies in a rapid and paranoid conquest of the Americas. The Britannian identity was born from the mythologising of British culture in response to the sheer number of Amerindian, European and Hispanic subjects.
The Holy Britannian Empire is the supreme world power with an empire that controls over a third of the worlds surface. Britannia is a traditionalist, Social-Darwinist, hierarchical nation with a strict class system. Society in Britannia is conservative though women are given equal opportunities for employment and achievement as long as they are capable of doing it on their own strength. Britannia is an absolutist government with the Emperor as the head of state and government with the Senate handling the administration delegated to them by the Emperor and the aristocracy governing the provinces on behalf of the Emperor. Britannia is a capitalist society that is supported by the ideals of the empire and has allowed it to become very prosperous despite the authoritarian state of the empire. Britannian society is a class system with the aristocracy and corporate families at the top. Society for the Britannian citizens is decided by income but prosperity is guaranteed for any citizen through the labour of the Numbers. Numbers are the lowest rung of the social ladder with a few exceptions of puppet leaders that were given privilege after the conquests of their nations.
Life for numbers in the Britannian Areas is horrendous. Numbers are actively discriminated against by Britannian citizens and are often exploited as cheap physical labour. Numbers are consigned to ghettos where squalor is common and is just as likely to result in death as accidents at work. In the older areas the ghettos are government built and under more progressive Viceroys looking for a continued work force would often have basic communal services. Numbers do have the option of honorary citizenship which allows greater status in society as technical first class citizens. However strict requirements are necessary and the Honorary Britannian will still be subjected to discrimination by pure blood citizens. The easiest way to gain citizenship is to join the army where benefits are guaranteed along with a higher salary. Honorary Britannians will often be used by the army as cannon fodder.
The current Emperor Charles Zi Britannia is a devout believer of the ideals of the Empire. Since his rule began the exploitation of the Areas has grown worse and often corrupt nobles have found that their power has become an even stronger shield when engaging in illegal activities whilst citizens and Numbers all suffer for it. The Emperor is a self acknowledged polygamist that has over a hundred wives and consorts but only a few of his most powerful wives have given him children. Charles considers all his children legitimate in their claims to the throne and uses the right of succession as a tool to decide his successor by pitting his children against one another.
The European Universe is Britannia's main rival. The EU was developed from the empire of Louis Vanqoeur after his assassination at Waterloo. His son inherited his vast and complex empire and was unable to exert the control his father had. The Empire held together but decentralised as puppet states began to express their own identities and rights. The EU is now a federal democratic society that upholds the ideals of self-determination, human rights and democracy. Monarchy is still present in many nations across Europe and the rest of the Union but by now numerous republics exist. Despite their ideals the EU is definitely Eurocentric with much of Africa still economic dependencies that receive minor assistance in their development. The EU is a far more liberal society than their rivals but by OTL standards is conservative and militant. The EU is cosmopolitan with new social fads appearing from across the EU along with a surprising tolerance of culture language and religion. Despite the prevalence of French as the lingua franca of EU government and France still being the figurehead of the EU there has been a shift in power. Germany is the centre of science and research in the EU, Russia is the most economically productive and Britain exports the most cultural influence these days.
The EU decolonised after the Great War/1st Pacific War. Despite loosing their Asian and Pacific colonies to the Britannians and Chinese the EU was able to retain nominal control over their African colonies. All of Africa is still under Europe's thumb in some way or another. Several African states that received sufficient development and colonisation before decolonisation have managed to become fairly prosperous and influential enough to qualify for status in the Hemicycle. The EU is a heavily fortified nation with an enormous complex system of defensive structures designed in the event of invasion by the Britannians or the Chinese. The EU state security does have a lot of power despite the EU's ideals and conscription is universal in every EU state.
Butterflies lead to different leaders in China that managed to modernise the nation before the 19th Century. There was no century of humiliation for the Chinese and they even managed to hold off powers like Russia and Japan. China's enormous population made it incredibly powerful once industrialisation became large scale in China. During the mid 19th Century China suffered a civil war during he period of industrialisation and the old Qing Dynasty was overthrown by the previously obscure but progressive Jiang family who established their own dynasty. The Chinese Federation is a strange nation with an absolute monarchy, a federated political system and a socialist economy. Much of society excepting the socialist ideals is still very traditionalist.
A major partner in the Chinese Federation is the enormous and economically strong Indian Raj. India was liberated from French rule during the 1st Pacific War and remained united due to Chinese guns before a new arrangement could be worked out. Other members of the federation have been liberated by the Chinese from European control after the Great War/1st Pacific War. All the members of the federation accept the Empress of China as their monarch. The current Empress Jiang Lihua was placed on the throne at age six and has been dominated by her corrupt subordinates the High Eunuchs that have stolen the wealth of the nation in order to live in luxury. Due to this corruption much of the Federation is in the grip of almost crippling poverty.
The Republic of Australia was founded by British colonists and was strengthened by Europeans fleeing Vanqouer Europe or Britannian America. Australia is an officially neutralised nation but does house several Britannian military bases on lease to their government. Australia is genuinely democratic and is often the destination for any seeking political asylum.
Japan modernised like OTL but failed to establish themselves as a colonial empire due to a stronger China. Japan joined in the 1st Pacific War but was defeated. The government reformed into a constitutional monarchy. Japan has always been the owner of the worlds largest deposit of the super-conducting mineral Sakuradite. Since their failure at military conquest the Japanese have begun exploiting the poorer nation states of the Chinese Federation and EU as much as they can and have begun to set themselves up as a fourth superpower on economics alone.
The year is now 2009 and the biggest news is the recent assassination of Marianne Vi Britannia a former Knight of the Round and the favourite consort of Emperor Charles. This was subsequently followed with the political exile of her young son Lelouch Vi Britannia and traumatised and crippled daughter Nunnally Vi Britannia who have been sent to Japan as political pawns for the Emperors plans for military expansion as tension rises between the three powers and the increasingly arrogant Japanese.