Mount Vesuvius

After the eruption of Avellino in 1995 BC, the volcano passed into a state of more frequent but less dangerous eruptions.

An excerpt from the article 19 facts about Mount Vesuvius
This situation remained until 217 BC, when Vesuvius made its presence felt again. Apparently from 217 BC to 79 AD the area was quiet and the slopes of the volcano were covered with vineyards and gardens. During this blissful period of 295 years, people forgot about the hidden power of the mountain and probably therefore underestimated the earthquakes that preceded the destruction of Pompeii and Herculaneum.