Question: Which style guide recommends using Vergilius to avoid confusion with Virgilius Maro Grammaticus?
Sentence: Alternatively, some argue that Vergilius was altered to Virgilius by analogy with the Latin virga ("wand") due to the magical or prophetic powers attributed to Virgil in the Middle Ages (this explanation is found in only a handful of manuscripts, however, and was probably not widespread).
Answer in sentence: no