Juvenal's Satire IV describes the presentation of a turbot to Domitian, who calls a meeting of his council to discuss what to do with it. At a less exalted level, Marcus Didius Falco had a similar problem when presented with a turbot by Titus, Domitian's elder brother, in Venus in Copper, one of our December reads.
Wikipedia (usual caveats apply) has a short article on turbot, with a not very helpful illustration. A rather better illustration, giving some idea of the size can be seen at the bottom of this angling page. 25lbs 12 oz works out at 11.68 kg.
So, should you be fortunate or unfortunate enough to be presented with a turbot, what do you do with it? The BBC gives us 17 recipes for turbot.
