AHC: German or Dutch as the Lingua Franca of the World

I know the PoD's temporal limits do not allow it, and technically speaking it won't be Standard German or Dutch but a different version of High German, but the AHC would otherwise be perfect for certain versions of a super-successful HRE/Carolingian Empire. Namely, the ones where the language of the Imperial court became the lingua franca of the empire, and the capital stayed in Aachen. ITTL the Carolingian Empire never broke up or it reunified for good after a relatively brief division (100-150 years at maximum, depending on the PoD). It gradually centralized at a sufficient level to be a functional state, even if its sheer size and diversity meant the system always kept a sizable federal component up to modern times. Its expansion and consolidation united Europe, the Mediterranean, and the Western world in political, cultural-linguistic, and religious terms. It absorbed southern Italy and Central Europe up to the outskirts of Russia, waged the Reconquista to a successful conclusion, and extended it to conquer North Africa.

It gradually assimilated the British Isles and Scandinavia by a mix of growing dynastic ties, imperial influence, and the occasional military intervention to put down particularist opponents of union. By pretty much the same means combined with strategic cooperation against the common Muslim and steppe nomad enemies, it got a closer and closer relationship with the Byzantine Empire up to political union and the rebirth of a bigger and stronger Roman Empire. Successful Roman wars against the Muslims kept Anatolia in Christian hands and led to conquest and forced assimilation of Egypt-Nubia, the Levant, and Mesopotamia. Islam suffered a decisive defeat and near-fatal collapse, losing pretty much all its core lands but Arabia and Persia. Waves of Muslim refugees fleeing Roman conquest and forced re-Christianization of North Africa and the Middle East helped Islam reinforce its grip on Central Asia and West Africa, but that was it. It was quite unlikely in these circumstances Islam would be in any condition to make serious inroads in the Indian subcontinent or the Malay archipelago, unless perhaps the aforementioned refugees turned out to be extremely successful as conquerors of India.

Success of the HRE sent Christianity on a development trajectory that kept it mostly united, preventing or reversing any equivalent of the Latin-Greek schism, the Calcedonian schism, and the Reformation, and letting the Church stay subservient to political authority. Heresies got suppressed or expelled beyond the Empire's borders. Mutual reinforcement of the ideals of Roman and Christian universalism made the notion of union of the Western world irresistible for members of its civilization and helped the empire ultimately recover from any crisis, much like it happened for China.

Imperial peace and unity significantly accelerated the recovery of Europe from the collapse of the First Roman Empire. Technological development enabled Roman Europe to progress into the Age of Exploration, global colonization, and eventually industrialization and the Information Age, just like OTL if somewhat earlier. Exploration of the Vinland route led to Roman discovery of the New World and colonization of huge swaths, in all likelihood the vast majority, of the lands that Europeans could easily conquer and comfortably settle, including the Americas, East Africa, Southern Africa, and Australasia.

Roman Europe successfully colonized and assimilated most if not all of those areas thanks to its vast superiority vs. native states in terms of technology, organization, resources, and population. A few areas here and there of relatively limited size and value might escape such a fate by becoming homelands for political-religious European dissidents, East Asian or West African colonizers, or the rare Amerindian culture that was able to bridge the gap with Eurasian ones. Successful independence movements of European colonies were theoretically possible but rather unlikely in practice since the power gap with the moterhland was too high and potential external support for separatist movements too scarce.

Early contact with Europe drove the sophisticated South Asian and East Asian civilization to modernize timely and successfully enough to avoid European colonization and remain in the same league as Roman Europe, even if the latter always stayed the alpha dog of the world and dominated global trade. West Africa and Central Africa likewise were spared colonization by looking too inhospitable to Europeans. The HRE became a multicontinental hyperpower that utterly dwarfed any other state and civilization in political, economic, military, and cultural terms, with a population of one-third of humanity.

As technological progress drove society down the road to modernity, the effects of mobile printing, mass public education, and the mass media gradually made the lingua franca of the HRE, originally the court language of the Imperial capital in Aachen, the native language of the overwhelming majority of its inhabitants. All the other Germanic, Latin, Slavic, Celtic, and Greek languages within the European core of the HRE suffered radical decline and marginalization during this process, mostly keeping only academic relevance. The non-European languages in the areas conquered by Roman Europe got nearly wiped out as a result of colonization. Even outside the HRE's borders, its global hegemony caused its national language to become the undisputed lingua franca of the world since the beginning of the modern age.

As it concerns fulfilling the AHC with a post-1500/pre-1900 PoD, it is relatively easy to fulfil in AH terms. Let the HRE/Germany centralize/unite sometime between the 16th century and the 19th century, the sooner the better, in a way that allows it to seize/keep control of all continental Germanic-speaking areas and/or all the areas traditionally claimed by the HRE. Expand such control to include all of Italy, Poland, and the Habsburg lands, and consolidate this resulting Mitteleuropa core to federal levels of integration. Use the resulting resources to win all the inevitable wars with the other European powers that oppose your rise to hegemony. Kick Britain out of the continent, push Russia back into its pre-1800 or better pre-1700 western borders, dismantle the Ottoman Empire, assimilate defeated France and Spain in your empire, turn the Balkans and the Eastern Mediterranean in a constellation of client states. Depending on the POD, either prevent the rise of the British Empire and replace it with the Germanic Empire, or dismantle it. Colonize and assimilate in your federal system all the valuable places that may be filled with European settlers, be content to exercise indirect control on the rest. Bask in the superpower hegemony these achievements would enable, and let the German Language naturally rise to the state of global lingua franca as the result.

Means may vary from the 16th century Habsburg winning the power struggle against France, the Ottoman Empire, and Germanic/Italian/Iberian particularists and taking a practical attitude to religion, to Austria and Prussia fusing in one state by dynastic means or making a power-sharing compromise to centralize the HRE/Germanic Confederation, to the 1848 Revolutions succeeding in a way that causes the rise of a German-led EU equivalent, to Bismarck completing his life's job by dismantling the Habsburg zombie, taking its choice bits, turning Italy and Hungary into loyal sidekicks and Russia into a semi-reliable ally by giving them the rest and supporting the Russians doing the same to the Ottoman terminal case, and his successors using the resulting power base to defeat France and Britain.

Well, the 30YW was so destructive to Germany that IMO a PoD that occurs before or during its period and is supposed to be beneficial to the German nation should avoid it or tone down its damage considerably, not make it even worse. I agree that in order to centralize the HRE some kind of military reckoning with the particularist German princes was in all likelihood necessary and inevitable, but it could (and for the purpose of this scenario should) be done with something much less devastating than the OTL conflict, and somewhat less tied to extreme religious antagonism. My tentative idea for this is to get a different kind of division of the Habsburg domains either before or after Charles V that keeps the Burgundian inheritance in the hands of the German branch and at the same time drives the German emperors to adopt a more pragmatic and tolerant policy toward the moderate wing of the Reformation, starting with Charles V himself.

I agree that ruthless repression of the radical wing of the Reformation was necessary for any German emperor, given the violent anarchic extremism of the Anabaptists and the strong hostility of the Calvinists to royal power. However a compromise with Lutheranism that bargained religious tolerance for neutrality in the struggle between the centralizing emperors and the particularist princes was feasible and beneficial to both sides. A division of the Habsburg inheritance may take place either before Charles V, with a survival of Miguel de la Paz that ensures the unification of the three Iberian monarchies under the Aviz-Trastamara dynasty, or after him, with Charles making a different abdication settlement. Perhaps the former is better, so Charles can spend his entire reign focused on German issues and not have his religious policy tainted by the influence of militant Spanish Catholicism. In any case, Spain and the HRE should stay close allies against France and the Ottomans even if they get different monarchs and religious policies, but this seems relatively easy to accomplish, since they shared complementary strategic interests.

They just need to make a sensible compromise settlement about Italy, but this does not seem hard to do. I am not sure in this regard if Milan should better go to Spain or to the HRE. Quite possibly, Habsburg HRE and Aviz Iberia may agree on a joint effort to shove a thorough reform of the Church down the throat of the kicking and screaming Popes which adequately deals with the issues that triggered the Reformation, transfers power from the Roman Curia to 'national' Churches, and lets the secular governments seize the excess wealth of the Church. This would enable the Emperor to take the lead of religious reform in Germany (not unlike what Henry VIII did in England) and meet the Lutherans mid-way.

At the very least, the result of this Spanish-German strategic cooperation should ensure French expanionistic attempts are entirely frustrated (but if the allies can grab Burgundy and/or Provence, even better), the Ottomans stay out of Hungary (of course, the more they are kicked out of the Balkans, the better), and Barbary states piracy is crushed (if Spain can make a serious effort to conquer North Africa stick, even better). This should prevent the Dutch rebellion (ensuring a separate Dutch identity never arises and the Low Countries stay an integral part of Germany, like Bohemia-Moravia, Switzerland, and the lands beyond the Meuse) and grant the Habsburg a sufficient power base to crush the particularist princes in a earlier, shorter, and less destructive equivalent of the 30YW, ensuring success of a centralization reform of the HRE. Such a victory should enable the Habsburg to seize the lands of at least a few among the rebellious princes, such as Saxony, Brandenburg, and/or Brunswick-Luneburg (the more the better), and add them to their domain.

It is probably unlikely that even a realistic degree of decisive Habsburg success would enable establishment of full-fledged Imperial absolutism. However, turning the HRE into a functional federal monarchy should be entirely feasible, with a power-sharing compromise between an Emperor with strong executive powers who keeps full control of administration, finance, foreign affairs, and the military, and an Imperial Diet, which has an important say about taxation and the laws of the realm. The Imperial Reform of Maximilian I should be further extended and completed with establishment of a full-fledged three branches of government system, with the Imperial Diet as the legislative authority, the Emperor and his ministers as the executive, and Imperial Chamber Court as the supreme judiciary. The Imperial Circles system should be implemented throughout the HRE's territory, to rationalize taxation, the raising of troops, and representation in the Diet. Much like the particularist princes, the Swiss Confederation had to be crushed on the battlefield (not too difficult since it was in military decline in the 16th century) and fully reincorporated in the Empire.

A mediatization reform was necessary to reduce the political fragmentation of the HRE and rationalize its internal borders, and a parallel secularization reform to eliminate the ecclesiastic principalities. Of course, the Habsburg domain should reap the lion's share of territorial benefits from these two reforms, although a sizable part of the leftover booty may go to reward the German allies of the Habsburg. To a degree, the Emperors should cultivate a political alliance with the minor nobles, the burghers, and the Imperial cities to counterbalance the power of the princes. The HRE may stay a de jure elective, de facto hereditary monarchy, since in these circumstances the power base of the Habsburg is going to be so large they always have the Imperial election in the pocket barring political catastrophes. The Electoral College should be reformed to a system based on the Imperial Circles much like membership in the Imperial Diet, to make both fully represenative of all HRE territories.

With this kind of settlement the HRE should have no serious trouble becoming the strongest European state, outstaging France (and down the road, Russia) and frustrating all its expansionist attempts, ensuring the Germanization of all its territories, keeping a solid personal-union bond with Hungary, and helping it expel the Ottomans from the Balkans. I am not sure if in these circumstances it would better for Germany to pursue hegemonic control of northern Italy and an extension of its federal system beyond the Alps, or hand over the job of Italian unification to its Spanish ally. Certainly a HRE/Germany that centralizes since the 16th century and keeps control of the Low Countries is going to be in an excellent position to take part in the colonial game on a level playing field with the other European powers. The Spanish colonies would be off-limits for German expansion, also because Germany would have a serious interest to keep cultivating an alliance with Spain as long as feasible to keep France, England, and the Ottomans at bay. The same point applies to the Portuguese colonies, since ITTL the Iberian Union is going to endure. On the other hand, Germany can and should outstage Britain and France in North America, India, Southeast Asia, and Australasia w/o excessive trouble. With a little effort, TTL Germany can win an equivalent of the French and Indian Wars and turn North America north of the Rio Grande or better the Tropic of Cancer into a German colony.

As it concerns Poland, I agree the minimum agenda for this kind of successful Germany should be to ensure the Poles never get funny ideas about Pomerania and Silesia, seize territorial continuity with Ducal Prussia and control of the Vistula trade route by conquering Royal Prussia, enact full Germanization of these territories, keep Poland out of Russia's hands, and optimally make the PLC a client state. I am not convinced in these circumstances a drive to conquer and Germanize the Baltic states would be worth the effort, although Germany should certainly strive to keep them out of Russia's hands.