Author, or compiler, of two sets of questions and answers appended to the Urmia recension of Theodoros bar Koni’s ‘Scholion’, as well as of some of the additional passages in the body of that recension. The first collection of questions and answers, in 20 sections and bearing the heading ‘matters (šarbe) [taken] from the books of non-Christian authors (barrāye) and philosophers, collected by Mar Silwanos, bishop of Qardu’, deals with such subjects as atheism, astrology, determinism, dualism, the problem of evil, angelology, and superstitious practices. The second collection, with 44 questions, deals with philosophy in general and with the subject matters of Porphyry’s ‘Eisagoge’ and Aristotle’s ‘Categories’ and ‘On interpretation’. A significant part of the materials in the second collection overlaps with those in Bar Koni’s ‘Scholion’, and many of the passages found there also reappear in the lexicon of Bar Bahlul. This Silwanos is no doubt to be dated after Theodoros bar Koni and is therefore to be distinguished from ‘Silwanos, bp. of Qardu’ who is said to have visited Rabban Hormizd (7th cent.), the eponym of the Monastery of Rabban Hormizd, while the latter was still a young man (‘History of Rabban Hormizd’, ed. Budge, 37–9).