1836-48 -- The empire is united, by this point the kingdom of Hungary meant little more than another jewel on the Kaiser's crown. Hungarian is an accepted culture within the borders of the old kindom of Hugnary, and I guess the same goes for Croat in Croatia-Slavonia.
The revolution of 1848-49
1848 April -- According to the
April laws Hungary-Croatia separates from Austria, the Kaiser rules the nations under a single crown, a personal union. At this point, unless Austria does something unexpected during the previous 12 years, Hungary should be released as a satellite of Austria.
1848 April-August -- Serf-emancipation in Hungary, the newly formed Hungarian parliament is however incapable to give an adequate response to the minority question, the tensions rise between minorities and the Hungarian majority.
1848 August -- The Serb-Croats ask the Austrian crown for intervention. At this point Croatia-Slavonia should rejoin Austria.
1848 August 31 -- the Kaiser denounces the April laws and sends and ultimatum to the Hungarian parliament (Austrians and their ultimatums....) that unless the April laws were to be renounced military intervention is to be expected. The Hungarian parliament unequivocally declined these demands. At this point should be released and Austria declares war on Hungary with a reconquest/restoration of order casus-belli, Hungary becomes fully independent with Lajos Batthyány as temporary head of state. Should Hungary stand victorious the path to becoming either a Kingdom or a Republic should be open.
1849 late spring -- The Hungarian Revolution stands strong and the forces are successful at defending the homeland, at this point victory seems inevitable.
1849 may 21 -- The Kaiser enters into an alliance with the Tsar, Russian intervention begins. It is very likely that without this intervention, the achievements of the Hungarian revolution would have spread northwards and eastwards and similar revolutions might have happened on Polish and the Baltic grounds. In otherwords it was in both Austria's and Russia's best interest to suppress this flame of liberty and self determination.
1849 late July -- Arthur Görgei Hungarian general tries to outmaneuver the Austrian diplomacy by offering the crown of Saint Stephen to a Russian grand princess. This might be an interesting alternative scenario, Hungary becoming the satellite of Russia and the war continuing between Russia and Austria.
1849 August 13 -- the united Hungarian forces lay down arms at Világos (near Temesvár). This is usually regarded as the end of the revolution. Austria reannexes Hungary.
1851-1858 In Hungary we know this as the Bach-era. An era of oppression by the Austrian authority and passive resistance by the Hungarian intelligentsia. Although many achievements, such as the emancipation could not be revoked, the Austrians tried to revert as much of them as possible as retaliation. This era was also marked by waves of Hungarian emigrants. Hungarian should not be an accepted culture during this era however Croat should stay accepted within Croatia-Slavonia.
1859-1867 With the Kaiser denying his help to Russia in the Crimean war and losing his Italian holdings and Italy proclaiming her unity, he could no longer afford bitter enmity within his ethnically very diverse empire. This was the end of the Bach-era' oppression, these are the years that paved the road towards the Austro-Hungarian compromise of 1867. Hungarian should again become an accepted culture within the old borders of the kingdom of Hungary.
1867 -- Austro-Hungarian compromise. Main points of the compromise:
-Kaiser Franz Jozef is the single head of state of both Austria and Hungary, the Hungarian parliament was reestablished
-Austria-Hungary became a common entity, with common diplomatic and military affairs with common finances regarding these two issues.
-However the two entities with the exception of these two issues ran their own affairs, including international commercial treaties and trade agreements.
-Customs union which had to be renegotiated every 10 years.
In game terms, in my opinion Austria-Hungary should stay as a single entity, an independent Hungary on map can be argued for but in the end I don't see much merit in the idea as it would be a massive burden for both the player playing as Austria or the AI trying to coordinate its subservient subject. The two countries conducted their foreign policy as single entity and had a single army but had separate domestic policy. I think this could be represented as Hungarian becoming the primary culture within the borders of Hungary and German becoming an accepted one.
1868 -- Croatian-Hungarian settlement. A compromise between Hungary and Croatia that went in a similar fashion. Croat should become the primary culture in Croatia-Slavonia with Hungarian and German becoming accepted and in turn Croat becoming accepted in Hungary. A note here, the Adriatic port of Fiume (Rijeka today) was officially part of the Kingdom of Hungary since the mid 18th century, meaning the rules of Hungary should apply to this special province.
Every 10 years the union could be renegotiated with the possibility to add more members such as Czechs, Slovaks or Poles thus allowing the player to slowly become a true Danubian Union.
Attached a map as a guide for the geographical territories I have mentioned above