Which version of the Bible was used in the Middle Ages?The version of the Bible most widely used during the Middle Ages (especially around St Thomas's time) was the Vulgate, that's the short answer. The Vulgate was translated into Latin from the original texts by St Jerome (d. 420). The main reasons why the Vulgate became so widely used were: its clarity of exposition, the fidelity of its translation and its elegance of diction. By the 9th century it had been adopted by most of Christendom as the most authoritative translation. You can read a very good summary of the history of the Vulgate up to the 20th century by clicking on this link.
What exactly was an articulus?
The articulus, explains Pieper on his Guide to Thomas Aquinas, was the smallest building block of the quaestio disputata (and other forms of writing). It typically contained the following parts:
The question under discussion;
the opposing arguments to the idea the author was going to submit;
an idea contradicting the arguments (n. 2);
the thesis, a synthetic statement where the author advances his own reply to the question (n. 1).
a development addressing each of the opposing arguments (n. 2).
For a good example of this check the structure in any of the twelve articles of Question One of Aquinas's De veritate (the reading for our July 2019 session).