The largest surviving body of Pliny's work is his Epistulae (Letters), a series of personal missives directed to his friends and associates. These letters are a unique testimony of Roman administrative history and everyday life in the 1st century AD. Especially noteworthy among the letters are two in which he describes the eruption of Mount Vesuvius in August 79, during which his uncle Pliny the Elder died (Epistulae VI.16, VI.20), and one in which he asks the Emperor for instructions regarding official policy concerning Christians (Epistulae X.96).