How do historians have learned about the volcanic eruption that destroyed Pompeii?

Historians have learned about the volcanic eruption that destroyed Pompeii primarily through archaeological excavations, which uncovered well-preserved artifacts, buildings, and even human remains buried under volcanic ash. Additionally, ancient texts, particularly Pliny the Younger's letters, provide firsthand accounts of the eruption and its aftermath. These sources, combined with geological studies of the eruption's layers, have allowed historians to reconstruct the events of 79 AD and understand the impact on the city and its inhabitants.