"Joachim Abbas" is Joachim of Fiore (1135-1202), a 12th century mystic from Calabria who became abbot of a monastic order (hence "Abbas") and who devoted himself to study of the hidden meanings of the Bible, especially those of the book of Revelation. His three manuscripts of apocalyptic philosophy became hugely influential, particularly for their innovative understanding of the divine plan for history. But Stephen has been looking at a later prophetic text falsely attributed to Joachim.

John Hunt 2014

Joachim of Fiore in a 15th c. woodcut, holding a book titled Apocalypsis Jesu Christi. Source:

Joachim's tetragrammaton, IEUE. The three interlocking rings represent the Trinity. Held in the Bodleian library, Oxford, MS. CCC 255A f.7v. Source: