Well, here they are, then. Part one, focussing on the Byzantine Empire as it was in 769. It ought to be said that some of the governmental records that we have for the period aren't complete, and so there is a certain amount of fuzziness around some of the internal borders of the Empire; I'll point those out below.
Presenting the Byzantine Empire and the Sklaviniai (more on them below as well) in 769. Borders are in white, with national borders solid and internal borders in dashes; vassals are in blue; independent realms in red.
The Empire is in a state of administrative flux at this point, with the process of thematisation (that is to say, the merger of the civilian and military governance of each district; in previous periods of the Roman Empire, these two spheres had been strictly separate) that started in the Anatolian provinces as a measure to bolster defenses against the Caliphate now spreading westward into the Empire's European provinces. This process is not complete; it has occurred in Thrace, Sicily, Cephallenia, and Hellas, which are fully-fledged Themes under a Strategos who controls both military and civilian administration, but Sardinia, the city-states of the Adriatic, the Aegean Islands, and the coastal cities of Macedonia (including Thessalonica) are under a welter of Dukes, Eparchs, Judges, Magisters Militum, and Droungarioi. The general upshot of this is that these areas are still largely ruled by either civilian or military government, not the merger of the two that characterised the Theme system.
I'll discuss how I think each individual non-thematised part should be represented, but as a general rule of thumb, I would say each county should have a province modifier, "Civilian administration" or "Military administration," and that these modifiers should respectively lower the amount of levies/retinue from the province while increasing tax revenue OR increase the amount of levies/retinue from the province while reducing tax revenue. The Emperor should have some decisions available as time goes by to reform the non-thematised provinces into Themes (if they so choose), which would place them under "normal" feudal governance, removing the republican governments that some of them have, and remove the province modifiers. If the provinces are lost to the Empire, the modifiers should disappear also.
Thessalonica is at this point ruled by the Eparch, a position that is the (much-reduced) direct descendant of the Praetorian Prefect of Illyricum. The Eparch was a civilian official appointed from Constantinople; his position might be best represented by making Thessalonica a duchy title with no vassals and having the Eparch appointed from Constantinople, as is normal for Viceroys. At your discretion, you could give him Veria and Thessalia as vassals, but the Eparch's powers were very limited and the coastal cities largely independent at this time, so perhaps not. Thessalonica has the Civilian Administration modifier.
Veria and Larissa are fairly similar in terms of their situation at this time; the largest of a number of cities running down the coast of Thessaly, under tenuous Byzantine control. The cities are largely autonomous and self-governing, survivors of the old system of semi-autonomous city-states, and so should be ruled by their mayors as republics (county-level ones, not duchy-level merchant republics; we don't need them making trading posts all over the place). They might be under Thessalonica, but it would possibly be more accurate to have them as direct vassals of the Emperor, to reflect their near-total autonomy. They have the Civilian Administration modifier.
The Drungaries of the Aegean Sea and the Gulf are a pair of regional naval commands formed from the breakup of the large naval command of the Karabisianoi; they are at this stage independent of all the Anatolian Themes, including the Theme of the Cibyrrhaeots, the other successor to the Karabisianoi. The Drungary of the Gulf
may have Crete under his command; we'll return to this topic under Crete's heading. The Droungos of the Aegean Sea is actually quite a bit larger than the one province it has on this map, but the other parts of its territory, Chios and the Northern Sporades, are parts of other in-game provinces whose capitals were securely under the rule of different commands and Themes. The Drungaries of the Aegean Sea and the Gulf are the direct ancestors of the later Themes of the Aegean Sea and Samos, respectively, and the Emperor should be able to create those Themes at some point via decision, granting them bits of mainland Anatolia. The territories of the two Drungaries should have the Military Administration modifier.
Sardinia at this point is not thematised, and never will be, as it is lost to the Empire before the theme system spreads that far. Sardinia is a regular civilian province, ruled by a Judge who sits in Caralis; its military affairs are handled by a Duke, who rules in Forum Traiani, the modern Fordongianus, which is in Arborea county. Sardinia is, unfortunately, perhaps best represented in-game as a feudal duchy, since making it a duchy-level republic would also turn it into a merchant republic, which it certainly was not. Three of its counties should have Civilian Administration; Arborea should have Military Administration.
Venice and the Dalmatian city-states were at this point much like Veria and Larissa; fairly autonomous city-states, locally ruled and connected to the Empire only by naval power. The Theme of Dalmatia did not exist at this point, and so each of the states should be a county or barony directly under the Emperor. They should all be mayoral/republican, not feudal. Venice was already a great trading state at this time, and so should perhaps be a duchy, but that's up to you. They should all have the Civilian Administration modifier.
Dyrrachium is in a similar situation, the chief difference being that it's Greek rather than Latin. Mayoral/republican government, Civilian Administration.
Naples is very complicated, in a manner that I explained on the map itself; it is itself somewhat disloyal to the Empire, but its theoretical vassals, Amalfi and Gaeta, are considerably more loyal. You could represent the latter two states as vassals of Naples or as counties under the Theme of Sicily. Up to you, really. Naples and the other cities of the Duchy should have neither Civilian or Military Administration; civil and military authority had already merged in these provinces even without the Theme system.
Crete is poorly attested at this time. Prior to the Muslim conquest of the island, its exact governmental status is unclear. It may have been its own province, as it was in Late Roman times (in which case, it should be much like Sardinia - a feudal duchy with Civilian Administration), part of the Theme of Hellas, or part of the Droungos of the Gulf (in which case it should have Military Administration).
Abasgia and Lazica were a pair of Georgian principalities subject to the Empire. They should be feudal and hereditary, not Viceregal. No Civilian or Military Administration modifiers here.
The Balearic Islands and Cyprus, the edges of the Byzantine Empire, are in fairly similar situations despite their geographic distance; they are both co-dominions, ruled in part by the Empire and part by another power (in the case of Cyprus, the Abbasid Caliphate; for the Baleares, the Umayyads of Andalus). How you represent that is up to you. Vanilla CK2 has Cyprus split in half between the Abbasids and the Byzantines; that might work but it seems a bit clumsy to me.
Lastly for the Empire, we have
the Frontier Zone or No Man's Land between the Caliphate and the Empire in Eastern Anatolia. This was an area of constant raiding and counter-raiding under the firm rule of neither power. There isn't really a way to represent that sort of anarchy in CK2; you could perhaps give the northern two provinces to Byzantium, the southern one to the Abbasids, and make all three provinces start out with Depopulation, as if they'd been hit by plague.
The other independent realms as shown on the map are the
Sklaviniai, the small realms of various South Slavic tribes that existed on Byzantine territory. Unlike the larger and more independent Slavic polities further north, the Sklaviniai were somewhat politically affiliated with the Empire in a way that's hard to represent in CK2; their rulers were often appointed or confirmed by the Emperor, the territories in which they could settle were affirmed or approved by the Emperor, they sometimes fought in the Empire's wars (and just as often fought against the Empire), and the campaigns that the Byzantines fought against them at times are usually described as campaigns against rebels, rather than against outside enemies. They exist somewhere in between vassals and independent states, and my suggestion to model them would be to make them Tributaries to Byzantium. Some of the Sklaviniai would become part of Bulgaria over the next several decades, and some would become part of the Empire; they are realms on short notice in 769.
A final note on culture and religion; while the ruling class of each realm should be as they are laid out in my map, I don't really think the religious or cultural province setup should be changed much (if at all) from how it already is in the Old Gods start date. The Sklaviniai were generally very small in number and the areas they dominated usually seem to have been majority Greek or Albanian at the time.
It's good to see someone trying to do this again: I've always wanted to see one of these 769 conversions of HIP take flight. Some time ago, I did some effort-posts on the Byzantine Empire/southern Balkans setup for an earlier attempt to create a 769 start date for HIP, Vaguely More Historical. Would you be interested in seeing them?
