Thalamegos (Greek θαλαμηγός = conductor of the room (the rooms) of θάλαμος,-οι (thalamos, Pl-oi) = apartment, apartments, ἡγεῖσθαι (hegeísthai), lead) was a 115 by 14 m (377 by 46 ft), 20 m (66 ft) high, two-story Nile river palace barge. The huge twin-hulled catamaran was commissioned by Egyptian king Ptolemy IV Philopator for himself and his wife Arsinoe III ca. 200 BCE.
- Casson, Lionel (1995). "Chapter 14: Small Craft". Ships and Seamanship in the Ancient World. Baltimore: The Johns Hopkins University Press. pp. 341-342. ISBN 0801851308. http://books.google.com/books?id=sDpMh0gK2OUC&pg=PA341. Retrieved 17 June 2010.