Cyrillic
“both Jews and proselytes, Cretans and Arabians—we hear them telling in our own tongues the mighty works of God.””
— Luke (Acts) · Acts 2:11The alphabet of roughly a quarter-billion people exists because two ninth-century missionaries needed Scripture in Slavic.

Image credit & licence
Гибаничар · CC0 · File:Romanian-kirilitza-tatal-nostru.jpg (letter mistake)
Original image and licensingWhen Moravia asked for preachers who could worship in Slavic rather than Latin, two brothers from Thessalonica went one better: they invented a writing system for the language. Their students' final form of it — Cyrillic — now carries Russian, Ukrainian, Serbian, Bulgarian, and more. The alphabet of empires began as a translation project.
This label distinguishes a factual historical record from the interpretation built around it. A well-documented event or influence pathway does not prove that no alternative history could produce a similar result. Grade note: the historical record and pathway are especially well established
Cyrillic was later engineered by state scribes — built for liturgy, spread by empire; both halves are true.
