"he's been building pleasure-barges of cedar wood"

Bronze decoration from one of Caligula's ships
Creative Commons AttributionBronze decoration from one of Caligula's ships - Credit: Anthony Majanlahti
Suetonius, in The Twelve Caesars, refers to galleys commissioned by Caligula, with "their prows studded with jewels, their sails of many colours, whose ample interiors housed baths, porticoes and dining rooms, as well as a large variety of vines and fruit trees, so that, lounging on these vessels, he might travel by day along the shores of Campania, entertained by choirs and orchestras."

It is unclear whether Graves, when writing I, Claudius, was also aware of the archaeological discovery in 1927 of two enormous ships from Caligula's time on Lake Nemi. The largest of these appears to have been a floating palace, with baths and mosaic floors. The ships were being excavated and consolidated as Graves wrote.

Photo of excavated ship