for the most part on the above image, if i did not know the name of a historic entity, I left is blank, and the only non-historic enetiy I have named, that being Numerius, who is credited with changing the western roman empire into the kingdom of Ravenna
now, the tree needs some explination;
the familly trees are colour coded, and to make a full understanding certain marriges are coupled with certian events; first the colour codeing-
Western Roman
Eastern Roman/Byzantine
Ostrogothic
Lombard
Geat
now, the first half is rather easilly explained; Belisarius conqours Italy, and North Africa, accepts rule from the Ostrogoths, and to cement his rule, has his son marry the daughter of the ex-queen of the Ostrogoths, to give him even more legitimacy- his son becomes hier to the throne.
This has a very important impact, in that italy is now spared 18 years of draining gueilla warfare against renegade Ostrogothic nobles, and the Ostrogoths,by then setteld in the far north fo the Italy, and the slowlly being formed native italian military, that Liberius, when Preatorian prefect for Theodoric, had actually begun under the reign of the Ostrogothic kings of Italy and Rome, were sparred form this fighting; combined with the genral ship of Belisarius, these two elemts coudl be formed into a real corps of troops; and thanks to the tax system Liberius had also created under the Ostrogoths, the west was also generating money, without raising taxes.
However, all of this success was lost on the Lombards, who, as historically, invaded Italy, after, witht he aide of (as in history) the Byzantines and the Alans, conqoured the Geats, and subjegated them, the king of the lombards taking a geat as a wife; now, historically, the Lombard king Alboin got himself killed by his wife, who then fled to the exarch of the Byzantines in ravanna, because he had killed her father, mad his skull into a drikign cup, hung it at his belt, and made her drink from it; in this case, she was sparred having to kill him, by dear old Alboin getting himself killed by an early version of what woudl be come the dreaded Italian foot knight; this foot knight just happend to be son of Belisarius son; killing the king of Lombard took the fight out them, and a peace treaty soon ensued, with the grand son of belisarius marrying Rosemund, the former wife of Alboin; the Lombard becam subjects of the western empire, and had to evactuate all lands on the souther side of the danube river; restoring territorial integrity to the western empire in that quarter, and creating a buffer state completelly loyal on the far side of the danube- an invaluble ally when the Slav attempted to push into the region hard not long after.
the grandson of belisarius and his wife, the geat Roseumund had a daughter, who was married off ot the desecendent of Liberius; the two famillies had long been allied, and worked closelly together, and this was seen as the natural next step; particuraley since, with two generation of Barbarian blood behind the daughter, she didnt seem all the Roman, while the descendent of Liberius, by contrast, was full blooded; they married, and the child, Numerius, prooved ot be a capable ruler; changing the national language to the ever spreading italian dialect of Latin, as well as constituting other assorted reforms, he changed the western Roman empire, in both form and name, to that of the Kingdom of Ravenna, whom had a name, a culture, and a ruler suitible to all involoved.
by the tiem the scenario starts, the Postrogoths and lobards are seperate Duchies ruled by Ravenna, and Ravenna has gon and occupied much of th eformer Illyrian territory of old rome, preventign it from Slavic incursion; north africa, after a tiem when Ravneese rule was confined to little more then Carthage, has now, after the first crusade, recaptrued western northe africa, and maintians good relation with the islamic power, the muslim emierate of Tripoli located on thier eastern border