This is basically my own interpretation of
@Joshuapooleanox's Rome map up there, made before his write-up (so some parts may seem inconsistent). In my version, I've muted Rome's expansiveness somewhat, allowing it to lose some parts in order to consolidate others. As with the original version, Christianity never took hold in Europe, but I imagine the Roman, Greek, Egyptian, and in some ways Germanic pagan faiths would have coalesced into a worship of a Zeus/Jupiter figure. This ocurred everywhere except in Scandinavia, which is still strictly Germanic (though with more of an emphasis on Thor than Woden/Odin), and Pictland and Eira, which maintain primarily Celtic traditions.
Nationhood occurred in Germania as a result of pervasive Roman influence and various threats from the north and east. There are several German nations, each named for a tribe that either lived in its general area or moved somewhere else. Most of these states are under heavy Roman influence. Separately, the Republic of Britannia and the Empire of Dacia, while in the Roman sphere, broke away, and both are ruled by a Roman elite with local cultures and languages mixed in. Of course, in Britannia's case, the republic is more of an oligarchic dictatorship. In the north, an ambitious petty king in Norway successfully united several feudal kingdoms into a united 'High Kingdom', forming the Yarldom of Hordaland. ITTL, 'Yarl' is pretty synonymous with 'Khan' or 'Emperor', and it's rather fitting. They subjugated the Baltic area, bring Finnic, Sapmi, and Baltic peoples under their domination.
Rather than have a 'Slavia' in my version, I instead opted for the Vulgar Khaganate. It is basically a Turkic/Slavic fusion race similar to the OTL Bulgarians, though created out of migrations occurring at similar times. They are nomadic, but have pushed into Europe vigourously whilst fleeing from the rapidly expanding Kaskiri Khaganate. Both nations are firmly Tengriist with some local paganism throne in.
Christianity ended up spreading somewhat into Egypt, but was met with hostility and violence in most cases. In turn, it spread instead down the Nile through Nubia and into Axum, where it also made the leap across the Red Sea to southern Arabia. Islam never appeared, and there is no such person as Mohammad, with the Amirate of the Hijaz having condolidated religious fervour into the Cult of Hubal, and eastern Arabia becoming very Zoroastrian under Sassanid domination. I'm not sure of Buddhism itself would have risen by this point, but certainly something similar borne out of an attempt at escaping the Hindu caste system. Dobod is the patron of whatever faith this may be.
In the east, Han China took on a more naval tradition, vassalising rather than conquering as much territory as they might have OTL in mainland Asia. They conquered Taiwan for the jade, and ended up annexing the Ryukyus as well as an angry response to piracy from the islands, and Han trade fleets are present in the South China Sea and Indian Oceans.
I don't have a whole lot more to add to it. A lot of the place names are derivative, butchered from OTL, or completely made up, so I beg of you not to ask me too many questions about that.