It develops scenically on three levels, opening with gardens and pools towards the ancient coastline. It is one of the largest buildings of the entire city with an area of 3500 square metres. Upon entering, one accesses the peristylium directly, around which there are the most important rooms of the house, such as the triclinium. The beautiful garden is one of the most evocative areas. at the centre of which there was a triclinium covered with a pergola for summer banquets, and a pool. Two victims were found near the door that led to the service area, one of whom had a gold ring and a silver key as well as a hoard of 1356 sesterces.
The villa was one of the first buildings to be excavated in Pompeii and was a key destination for all travellers in the 19th century, as evidenced by the numerous graffiti that bear the names of famous travellers, such as the Count of Cavour. It is also used as the setting in the novel Marcella by Théophile Gautier.
It owes its name to Marcus Arrius Diomedes, whose tomb is located in front of the entrance.
Date of excavation: 1771-1774.