Many online history sites, and many non-academic books on Roman history quote two stories about the Emperor Domitian's dinner parties. One is the 'black' feast when he recreated Hades and terrified his guests, and the other is of him serving lettuce at a dinner party to torture his guests (Lettuce was a reputed soporific and they dared not fall asleep in the presence of the Emperor).
The black dinner party is from Dio Cassius. You wouldn't want to take everything in Dio Cassius as good history but he was at least a roughly contemporary source for the story. My problem is that I cannot find any primary source for the lettuce story. None of the secondary sources give a reference, and I cannot find it in any of the usual Domitian sources (Suetonius, Dio Cassius, the Historia Augusta, Pliny, Horace or Tacitus).
Martial gets closest, but does not actually link Domitian to Lettuces. He does have an epigram (13.14) that goes Claudere quae coenas Lactuca solebat avocorum (or avorum), Dic mihi, cur nostras inchoat illa dapes?
'Tell me why lettuce, which used to close the repasts of our forefathers, now commences our feasts?' Martial was contemporary with Domitian, and dedicated a couple of volumes of epigrams to him. That is as close as i can get to a primary source. The story does not seem to have been around in the early nineteenth century. In 1822 the Literary Gazette published an article on lettuce that did not mention it. It just said that by Domitian's time lettuces had moved from a final course to an Hors D'oeuvre. The reference is The Literary gazette and journal of Belles lettres, Arts, Sciences, etc. for the year 1822. London 1823 at p39.
I am beginning to suspect that the whole Domitian lettuce story is a modern myth that has become accepted as being based on a primary source that in fact does not exist, like the fable of the Romans sowing the ground around Carthage with salt after they defeated it.
Can anyone aim me in the right direction?
Thanks,
Howard Posner