Pandura

The ancient Greek pandoura was a long-necked lute with a small resonating chamber. It commonly had three strings. The instrument is found on several ancient Greek artworks, such as bass-reliefs and murals, dating back to the 3rd century BC. 

In Roman artwork, we see a modified pandoura, with a longer neck, sometimes a fourth string and often a plectrum. 

The replica we own, is based off the mosaic as pictured here. It is from Byzantium and dates from the 6th century.