Based on one of the “reality seeds” from GURPS Alternate Earths, which is my cheap excuse for the swarms of butterflies lying dead at my feet.
The current year is 1566, the PoD is Saxon victory in 1066. With the northern route of expansion cut off, Normandy instead turns its attentions towards trying to dominate France, triggering a rivalry with the southern Occitan-speaking realms who build up their power base in response. This all comes to a head when the Normans and the French crown use the emergence of the Cathar heresy in Languedoc to call a crusade as an excuse to crush Occitan power, but the Occitans manage to beat back the crusaders and establish an independent Kingdom of Aquitaine under the Trencavel dynasty with tolerance for Cathars and other religious minorities along the lines of Al-Andalus or Sicily (considerably strengthened thanks to being the main destination for Norman migration in the absence of England), then gradually conquered or inherited its neighboring realms, leading some to speak of an Occitan Empire. Meanwhile, England remained more closely tied to Northern Europe than Western Europe, strengthening northern trading networks and giving a boost to the Hanseatic League, closely intertwined with the Teutonic Order - the Order helped acquire territory for the League and German settlers, and the League increasingly took on much of the Order’s devout crusading spirit. This was accelerated by close ties with the Church, which turned north as much of the south spurned it with permissive attitudes towards heretics and infidels. Eventually the League fully subsumed the Order and grew more powerful than most of the region’s lords, and declared a Hanseatic Republic over which it would be able to exert more direct and centralized authority.
Today, the Occitan Empire and Hanseatic Republic stand at the head of two distinct cultural spheres, the Mediterranean world of courtly love and jousts, troubadours and polymaths of all faiths, and the Baltic world of Catholic burghers devoted to God and gold. Sicily and Andalus constantly jockey with Occitania for control of the former, while England has lately begun to assert its isolation and challenge the Hansa for control of the latter. Europe is in the throes of a renaissance, first sparked by the return of a native Andalusian dynasty to the throne in Cordoba and its vigorous sponsorship of the arts and sciences, and fuelled by the influx of wealth from the newly-discovered Hybrasil, where all the powers are vigorously attempting to colonize. All this has caused a great deal of social upheaval, with the greatest new wave of Cathar movements across Europe since the Black Death. The clash between the Occitan policy of protecting Cathars and the Hanseatic policy of crusading against them seems sure to spark a war between the great powers in the near future, and while both north and south have strong traditions of knighthood and chivalry they may not survive the new age of gunpowder.