It was a week the art world had never seen before. For the first time, an auction house sold more than $1 billion of art — over three days at that — a vast outpouring of money that amazed even the wealthy and the celebrities who flocked to the auction floor.

On Wednesday, Christie’s said it sold $658.5 million worth of work at its postwar and contemporary art auction, added to the $705.9 million for 20th-century works auctioned off on Monday. The billion-dollar threshold was a symbolic coup for Christie’s and seemed to widen the divide with its rival Sotheby’s, even if actual profits were unclear.

Sotheby’s on Tuesday raised $379.7 million, with fees, from 63 lots of American-oriented contemporary pieces. At its auction last week, it proclaimed the result, $368 million, as the second highest modern and Impressionist sale in its history.

“It’s a spectacle of excess at the highest level,” said Abigail Asher, partner in the New York and Los Angeles art consultants Guggenheim Asher Associates Inc., who was at Monday’s auction. “The last few years have been building up to this moment. A new class of buyer has entered the market and they’re prepared to pay staggering sums for trophy pictures.”