Sort:  

I must admit I needed to look arbiter elegantiarum up to be completely sure I understood it ;-)

He spent his days in sleep, his nights in attending to his official duties or in amusement, that by his dissolute life he had become as famous as other men by a life of energy, and that he was regarded as no ordinary profligate, but as an accomplished voluptuary. His reckless freedom of speech, being regarded as frankness, procured him popularity. Yet during his provincial government, and later when he held the office of consul, he had shown vigor and capacity for affairs. Afterwards returning to his life of vicious indulgence, he became one of the chosen circle of Nero's intimates, and was looked upon as an absolute authority on questions of taste (elegantiae arbiter; note the pun on Petronius' cognomen) in connection with the science of luxurious living.
Source wiki

Literally a judge of taste. But also in the meaning an authority. Because of the Roman focus on education they didn't judge between good taste and elegance, while we, after Rousseau and the noble savage, tend to often see the latter as something you are born with.

And if Satyricon shows anything it would be that good taste change a lot over time.

You are continuously expanding my horizons.

Taste does indeed change over time, but good taste hangs on a bit longer :-)

The gentleman above deserves to hang on to the end of the world.