The real question is not when did it cease but when did it begin?So true. It's simply a stylistic convention. Here's an image of a 14th century MS of the John Wycliffe (d.1384) translation of the
Gospel of St John (
link). The only capital visible is the one that starts the first chapter of the book. That was the style then. Interestingly enough, in the few transcribed versions of this passage which I consulted, the capitalization usage of today is used (
link).
Moving along to the Early Modern English period, looking at the William Tyndale (ca.1494–1536) translation (1526) of the same book (
link) shows no capitalization for the word
god either. By the time (1539) of the
Great Bible by Myles Cloverdale (1488–1568), we find capitalization (
link).
There are other English translations of the Bible to investigate, but I leave that as an exercise to the reader. So, the answer is probably sometime in the early 16th century.
