In 1115 Alphose-Jordan of Toulous dies of a fever. William X of Aquitaine thus has uncontested control of the County of Toulouse. He has a son when Eleanor of Aquitaine is born who managed to get ahold of Provence and Narbonne. Another heir takes Barcelona through marriage and force, the same for Valencia. A war by the King of France to regain influence over his unruly vassal ends in failure. Meanwhile in Italy, a noble family in Pavia seizes control and establishes themselves as Lords of the city, and eventually another family wrests control of them and raises themselves to the level of Dukedom. These Alt-Viscontis eventually conquer most of northern Italy and unify the region at Pavia. Al Eleanor of Aquitaine analogue emerges in Aquitaine and marries the scion of the Duke of Pavia who conquered most of Northern Itay. An alt-great Schism occurs and in return for favoring a claimant other than the one the King of France supports, that Pope elevates their grandson to the level of a King, establishing the Kingdom of [Insert name here]
Boom. The wealthiest region of Western Europe during the High Middle Ages is now all under one roof.