This is just a rough outline until I can fill in the details.
~30 CR: Death & Resurrection of Yahshua; Coming of the Spirit Most Holy
~ 50 CR: Ecclesia churches spread through Holy Land (Ainador) & eastern Pyralis
~ 70 CR: Predecessor revolt against the Suielman's is crushed, and the Predecessors are scattered. Ecclesiasts now effectively & quietly in control of the city.
~ 75 CR: In light of the persecution of the Ecclesia by the Suielman empire, the order of the Yeshuel is created to protect the Patriarch and the Bishops.
~ 100 CR: Ecclesia Churches spread through all of Pyralis and into much of northern Sonngefilde
~ 110 CR: The Sondeckis convert en masse to the Ecclesia faith. This presents the Ecclesia with an issue, as the Sondeck is a form of magic. The compromise reached, known as the Edict of Sondeshara, declares that Sondecki magic is a legitimate blessing from Eli and those born with this blessing are required to practice it. It also declares the means by which forms of magic can be tested. The actual practicing of magic is not performed with the sort of rigor as it should by later generations.
~ 150 CR: Ecclesia churches spread through Kitchlande and into Southern Sonngefilde. They are rebuffed in some places, such as Hevagn and Ebon.
~ 160 CR: The persecutions resume, and after Sir Bearn's martyrdom, the Order of the Yesbearn is created. Yesbearn knights have but one task, to defend Ecclesia priests from harm.
~ 200 CR: The first monasteries appear. They act not only as centers of spiritual growth, but also as schools, hostels, and hospitals for the poor. They also preserve the Canticles, and many other writings of ancient peoples.
~ 250 CR: The Ecclesia begins expanding into the Midlands, in the wake of the devastation there.
305 CR: The persecutions come to an end as the High Lord of Pyralis issues the Edict of Tolerance, permitting Followers to serve in the army and all public offices. Pyralis becomes the first country in Galendor to openly tolerate the Ecclesia. The other nations in the Pyralian Confederation quickly follow suit. In the years thereafter the Ecclesia gradually shifts from being a tolerated religion to the official established religion of Pyralis — the first monotheistic state on the continent of Galendor.