Translator of the Latin Vulgate
Jerome was the greatest biblical linguist of the ancient church. Commissioned by Pope Damasus I to fix the chaos of competing Old Latin translations, he made the then-controversial decision to translate the Old Testament from the Hebrew rather than from the Greek Septuagint — insisting on what he called the Hebraica veritas, the Hebrew truth.
Augustine wrote to him worried that going back to the Hebrew would unsettle congregations. Jerome went back anyway. The resulting Vulgate was the Bible of the Western church for over a thousand years and shaped Latin theological vocabulary permanently.
He was also famously irritable, and his letters are full of feuds. Scholarship and sanctity are not the same gift.
Between the last great council and the Ninety-Five Theses lie a thousand years that most Protestants could not summarise in a sentence. Monasteries, missions, schism, crusade, scholasticism, corruption and the reformers before the Reformation.
How the Bible travelled from Jerusalem to Alexandria to Rome to England, the theological battles fought over it, and the people who died to make it available.
What the deuterocanonical books are, why Catholics, Orthodox and Protestants differ, and how to discuss it without misrepresenting anyone.