Earliest related Latin evidence: c. AD 210 — Tertullian, Against Praxeas 25, related three-one theological language.
Early debated verbal evidence: c. AD 250 — Cyprian, On the Unity of the Church 6; the verbal relationship is debated.
Earliest explicit full Latin formula listed here: c. AD 380 — Priscillian, Liber Apologeticus 1, gives the Father, the Word, and the Spirit bearing witness in heaven and being one.
Earliest Latin Scripture-quotation witness listed here: Fifth century — Codex Speculum (m) contains the Comma in a non-continuous collection of Latin Scripture quotations.
Earliest extant continuous Latin biblical witnesses listed here: Seventh century — the Catholic-Epistle leaves of the Fragmenta Frisingensia and the León Palimpsest contain Comma forms. Codex Fuldensis, copied in AD 546, omits the Comma in its biblical text; its prologue is separate literary evidence.