OOC: I KNOW that Orthodox and Catholic Christianities didn't officialy split yet. De facto, however, they were as good as split by then.
IC:
880-933.
Viking Ireland's fortunes alternated between rise and decline. As the Magyars wrecked much havoc in Europe, Ireland's trade with France was disrupted. On the other hand, the trade with nearby England grew. Still, Ireland was increasingly overshadowed by said England, especially as there was no clear direction for Ireland to expand into. This was why Thormand II ordered many expeditions west, claiming Snowland (OTL Iceland) and parts of Iceland (OTL Greenland). Attempts to establish royal colonies in Affalon (OTL North America) failed due to bad weather and native resistance, however (apart from two expeditions - one dissipated amongst the natives, another settled down further south but lost contact with the king and that's what you get). Problematically, Thormand II was increasingly repressive and intolerant towards Christians... this had long-term, global consequences when an Irish mini-exodus took place, travelling to the holy St. Patrick's Island (OTL Newfoundland). The Irish Vikings didn't really bother back then, being too busy dealing with another case of Irish reacting to opression - namely, the Great Rebellion which was put down in blood. Viking Ireland swiftly begun to decline in early 10th Century.
St. Patrick's Island soon enough became to some a "paradise lost". Raided by one of the surviving Viking expeditions, the island was subsequently betrayed by some of the Irish who settled there and the short-lived monastic republic was replaced by a tribal despotism of Toton the Red (called so either for his beard, either for his habit of walking around in blood-soaked clothes). However, St. Communus, one of the Irish priests, led another exodus, to Nova Hibernia (OTL Nova Scotia). In spite of many hardships, Communus and his people have stalwartly persisted, improving their relations with the natives (a semi-legendary happening in which the natives voluntarily shared food with the Irish settlers and accepted baptisement is not very likely, but anyways) and allying with them against Patrickian raiders. The Vikings of Ireland already forgot about the whole affair about the western continent, especially as they lost war after war with Oswald's England, which in 924 finally took Dublin, uniting the British Islands. Irish Vikings fled to Snowland, and from there renewed raids against England.
Having conquered Ireland, the English expanded on their success by conquering Brittany and the Seine Region (including OTL Normandy), using the Second Holy Roman Empire's disintegration in circa. 900 AD. This eventually prompted the northern Francian quarreling chieftains, counts and kings to unify, in 932, under the rule of Ludwig I, the first King of Frankia (west of Rhine, north of Loire and Rhone, though this could be said to be a simplification, capital in Verdun). The southern parts of the deceased HRE, namely Aquitania, Gascony, Septimania, Burgundy and Provence (the Catalan counties seceded much earlier - more on them later), refused to acknowledge Ludwig and created the Kingdom of Occitania, with capital in Bordeaux. The first ruler of the new kingdom was King Pepin "III", officialy of the Carolingian line.
Further south, the Reconquista was beginning. Alfonso the Great (also known as Alfonsomagno) used the disintegration of the HRE well, allying with the Catalan counts - promising them protection and autonomy in exchange for allegience. Having beaten back, in 902, the armies of the Duke of Toulouse, Alfonsomagno has extended his rule over all of Christian Spain, and then used the instability in Andalusia (caused by Mozarabic rebellions and a Slav mercenary coup attempt) to expand southwards. Here, his trusty ungards were most useful - the Andalusian armies, already dismoralized, hardly had any combat experience against the Magyars, and hence were routed at Zamora and again at Albarracin. Modelling the rest of his army on the ungards in the event they would ever need replacement, Alfonsomagno advanced up to Tagus, albeit further progress was made impossible by strenghthening resistance and the truce between Mozarabs and 'Abd ar-Rahman III. Still, after his death in 912 Greater Asturia continued to prosper, beating back an Andalusian counteroffensive (during which 'Abd ar-Rahman III died, causing Andalusia to crumble further) and stabilizing its internal situation by promises of religious tolerance (rather limited in practice, but nonetheless) and by examplary execution of several Castillian rebels. By 933, Andalusia was conquered by Idrisids and confined to the area south from Guadaquilvir river, whilst the Asturians, having overcome the initial problems in integrating their vast new conquests (well, temporarily overcome), looked ready to consume the rest. King Garcia II had himself crowned in Toledo as Garcia I of... Spain. Some thought this to be this nation's finest hour.
They were wrong, as finer hours will come, but regardless, we must move onwards. Eastwards...
In Italy, the Pope and the Byzantines tried to reassert their respective power, coming into conflict with each other and allowing North Italian statelets to consolidate their own power. Result: chaos, which finalized in the creation of a "Holy Italian Kingdom" (HIK) in alliance with the Pope and just as loose as the Second HRE, whilst in the south, the Byzantines, bitter over Venice joining HIK (to gain de jure independance from the Byzantines, mostly), forced the Duchy of Benevento to acknowledge Byzantine rule, all while trying (unsuccesfully) to conquer Sicily.
Geldland fractured and reunited again a few times, eventually transforming into a feudal league under a konung who is essentially a glorified palace decoration. Christianity hardly made its way in this direction, due to the chaos in Germany, or as it was now known...
Severoslavia. Several Slavic tribes east from the Rhena (Rhine) and west from Wiszla (Vistula) feuded for much of the period amongst each other. It was not until Zhiroslav (voevod of the Sorbs, who eventually rose to power in Sorbia) in 911 subjugated the Western Poles and Bohemians, and gradually unified the Slavic tribes under his reign. An educated man, who in his youth lived in Constantinople, Zhiroslav eventually brought Severoslavia into the Orthodox Christian fold, often at the point of the sword, and accepted the name Basiliy. Zhiroslav/Basiliy's capital was at Broniborsk (OTL Berlin).
Why would such a faraway country as Severoslavia accepted Orthodox Christianity? It was not all that faraway from other Orthodox Christian countries, actually - specifically, Yenid Moravia, Magyar-ruled as it was, was under strong Byzantine influence and hence in 881 Istepan I, so greatly-respected and favoured by the Byzantines that he was allowed to adopt the title of Tsar of Moravia, officialy declared Orthodox Christianity to be the state religion of Moravia.
The Byzantine strenght grew and grew, as Edessa and Antioch were firmly placed under Byzantine rule. But the greatest wars of reconquest were yet to come...
In the overall, it seemed that Islam was on the retreat on all fronts... but as refugees, especially from Andalusia, fled for North Africa, the region's further development became possible, whilst missionaries penetrated deep to the south from Sahara. Islam spred. Swahili city-states gradually begun to emerge in the east, whilst in the west local but Islamicized states rose and fell.
Back in Europe, Prussia steadily expanded southwards, eventually occupying much of the Vistula basin.
Reno I Birger was a most outstanding "Nordic" ruler. Initially a minor Fennish general, he managed to manipulate his way into commanding an army sent to invade Holmland, whose king was insane and inpolite. After making him inalive as well, along with some of his troops, Reno suddenly came to a deal with Helmland's nobility, and became the king of Helmland. "Suddenly", it was discovered that Reno really was the legitimate heir to Fennland, yet for some odd reason was not in power there. Reno, emboldened by the fast victory in Helmland, embarked, in 897, to help correct this situation by conquering Fennland. Further along the line, Estland was conquered as well, and the new nation of Baltland rose, with the capital in Holmgard.
Reno also campaigned much against the Khazarified Slavs in the region. He attained some success north from the Pripet Marshes, but further south, as Khazars increasingly employed Ghuzz and Pecheneg mercenaries in the protection of their "allies", the resistance was harder to overcome, not to mention the logistics. One of those mercenaries was Mishael Barak (Barak is Hebrew for "Lightning" or "Storm") - he would one day be very important. Um, regardless, Khazaria continued to prosper in spite of the growing northern menace (that survived beyond Reno's death in 919). It also used the internal tensions of Dar al-Islam to gain greater influence over western Central Asia, greatly damaging Islam's expansion in the region. Finally, amongst the Khazars themselves Judaism continued to consolidate.