[Catholicguy]

For 12 centuries following, the mass droned on in Latin, with the vast, vast, vast majority of listeners having no idea what the priests were saying.

Incorrect. "Under Cyril (826 - 869) and Methodius (c. 815 - 885) the conversion of Moravia begins. The two brothers were sent by the patriarch of Constantinople to Moravia, where the ruler, Rostilav, decreed in 863 that any preaching done had to be in the language of the people. As a result, Cyril and Methodius developed the first usable alphabet for the Slavic tongue - thus, the Cyrillic alphabet."

Mass was in the vernacular

[ninenot]

Not being argumentative: was not the Cyrillic Mass actually Old Slovonian, thus incomprehensible to most peasants after, say, 1800?