The answer is: 79 AD
By the 1st century, the Pompeii area had a substantial population. Many of Pompeii's neighboring communities, most famously Herculaneum, also suffered damage or destruction during the 79 eruption. By coincidence it was the day after Vulcanalia, the festival of the Roman god of fire. The people and buildings of Pompeii were covered in up to twelve different layers of soil.