E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
King of the White Elephant. The proudest title borne by the kings of Ava and Siam. In Ava the white elephant bears the title of lord, and has a minister of high rank to superintend his household.
The land of the White Elephant. Siam.
To have a white elephant to keep. To have an expensive and unprofitable dignity to support, or a pet article to take care of. For example, a person moving is determined to keep a pet carpet, and therefore hires his house to fit his carpet. The King of Siam makes a present of a white elephant to such of his courtiers as he wishes to ruin.