Introducing Constantine II of Hungary

"King Constantine." You don't need to name him any more than that; everybody will know who he is, just as well as they'd recognize "Count Dracula." And for the same reasons.

The guy is hated across cultures.

Let's introduce him...

The Guerillas of Toleto

The survival of Moorish Spain (in the form of Seville) effectively stalls the southern expansion of the Roman Rite. Under various iterations of Moorish rule, the Mozarabic liturgy survives long past the point where it died out IRL.

It also means that the struggle within the Spanish Church over which Rite to use is more pronounced, and much more politicized, because the major players - Aragon and Catalonia - are extremely tied to the Roman Rite. Their efforts to push south (and not purely military ones; witness the Gonzalans) are going to be resented, and perceived as imperialism, by the Christians living under Moorish rule.

This most frequently comes to a head in the Primate of Spain: Toleto, a city (like Batallos) on the edge of both the Christian and Moorish worlds, and (unlike Batallos) one that changes hands at least twice during the Middle Ages. [details?] In Milan, attempts to suppress the Ambrosian Rite led to repeated riots. Attempts to do the same in Toledo are going to lead to what are called, in hindsight, the guerillas: the little wars.