The copper lamp - depicting the face of a wild, violent and drunken nymph - in the shape of a female head was found by a metal detectorist near Tadcaster.
It was then bought by the York museum, being one of only a handful ever discovered in Britain and in brilliant condition. The head is likely to be that of a Maenad, literally translated as raving ones.
In Greek and Roman mythology, Maenads were portrayed as frenzied, drunken and violent worshippers of Dionysus. Dionysus was the god of mystery, wine and intoxication. Liz Andrews-Wilson, finds liaison officer for North and East Yorkshire, said: "This was an incredible find by metal detectorists.
"The lamp is in amazing condition and it is very rare to find one in Britain. It was common at the time for such lamps to show these maenad figures. They were used by Romans as an example of what not to become."