Very wealthy, as in They're rich as Croesus, with their penthouse, yacht, and horses. This term alludes to Croesus, the legendary King of Lydia and supposedly the richest man on earth. The simile was first recorded in English in 1577.
Very wealthy. Croesus ruled an ancient Asia Minor kingdom who amassed a fabulous amount of wealth (he is also credited with having minted the first gold coins). How he would have compared to computer moguls and hedge-fund tycoons can never be measured, but his name lived on as someone who wasn't worried about where his next meal was coming from. “Rockefeller” was the late 19th- and 20th-century comparison: “He spends money like he's Rockefeller.” A Chock Full O' Nuts commercial included the line “better coffee Rockefeller's millions can't buy” until the Rockefeller family requested a change to “better coffee a millionaire's money can't buy.”