Berengar is assistant librarian, described by Adso as “vain” and “lustful”; his sexual desires and intellectual ambition both have tragic consequences. He is consumed with guilt after the death of Adelmo of Otranto, whom he persuaded to have sex with him in return for access to a mysterious book. He steals William’s glasses from the scriptorium at night in order to prevent him from reading some notes left behind by the murdered Venantius of Salvemec. William and Adso find him drowned in a tub in the infirmary, his tongue blackened with poison after trying to read the mysterious book, the pages of which had been poisoned by Jorge.