Sardanapalian \sahr-dn-uh-PEYL-yuhn\ , adjective:
Excessively luxurious.

Rich papers with gold borders, bronze chandeliers, mahogany engravings in the dining-room, and blue cashmere furniture in the salon, … all details of a chilling and perfectly unmeaning character, but which to the eyes of Ville-aux- Fayes seemed the last efforts of Sardanapalian luxury.
— Honoré de Balzac, Sons of Soil

Here, in this half-destroyed Tartar town, surrounded by steppes, he indulged himself in a Sardanapalian effulgence that beggared even his jassy Court.
— Simon Sebag Montefiore, Potemkin

First used in English in the 1860s, Sardanapalian is an eponym that comes from the legendary Assyrian king Sardanapal who was famous for his decadence.

via Dictionary.com