Junius was the first person to substantially study the Codex Argenteus (or Gothic Bible). He first showed an interest in Gothic in 1654, and engaged in a study of the Codex Argenteus in 1654. Isaac Vossius entrusted the codex to Junius. Vossius had secured the codex from Queen Christina as part of a debt settlement. MS Junius 55 is a transcript Junius made of the full text of the original manuscript. Junius engaged Jan van Vliet in his study of Gothic.