A sculpture of a goddess riding a chariot and a limestone bust of a woman's head upon which the sculptor Modigliani used to light candles are the centerpieces of an eye-popping 500 million pounds ($800 million) of art put on show at Sotheby's on Friday.

Alberto Giacometti's painted bronze "Chariot", one of six that the Swiss sculptor made in the 1950s, is expected by Sotheby's to sell for more than $100 million when it goes under the hammer at an auction in New York next month.

The limestone "Tete" (Head) by the Italian Amedeo Modigliani, who scavenged the stone he carved from a Metro constructionsite in Paris in the early 1900s, is expected to fetch in excess of $45 million.

"It's quite a room," Simon Shaw, co-head of contemporary and modern art for Sotheby's said of the gallery where the Giacometti and Modigliani dominated the floor space.

Three paintings by Mark Rothko were hung on the walls and a Van Gogh "Still Life, Vase with Daisies and Poppies" was visible in an adjoining room.

In anticipation of the opening next week of the annual London Frieze art show, where galleries from throughout the world show their wares to the world's moneyed art collectors, Sotheby's brought together offerings that will appear at several sales in the coming months.

In addition to paintings and sculptures, both contemporary and old masters, the items on display include a Patek Philippe watch known as "The Henry Graves Supercomplication".

Sotheby's describes it as "the most famous watch in the world" - and also the most expensive, with an estimated value of almost 10 million pounds.

The stars, though, are the Giacometti and the Modigliani, which Shaw said exemplify the huge increase in value for sculpture in recent years, a trend which began in 2010 when a life-sized bronze "Walking Man" by Giacometti sold in London for 65 million pounds, almost four times its pre-sale estimate.

"He's one of those artists like (painter Francis) Bacon who's been reappraised and with hindsight he is understood to have captured or represented a particular historical moment in the way that (Andy) Warhol represents the 1960s, Jeff Koons the 1980s or Damien Hirst the early 2000s," Shaw said.

He said Giacometti was inspired by the Egyptian sculptures that he saw in the galleries of the Louvre in Paris, and had made his goddess riding a chariot as "an image of hope and renewal".

Unusually for Giacometti, but in keeping with Egyptian sculpture, the figurine atop the chariot is bathed in a golden patina and the details of her hair, eyes, nose and mouth have been painted onto the bronze.

Shaw said the Modigliani was one of a group of "temple goddesses" that the artist kept in his Paris studio where he used to place candles atop them at night and he and his friends "prayed in front them and did a ritual thing".

The bust is instantly recognizable as a Modigliani for the elongated face. Shaw said the form showed the influence of African and Etruscan art on the artist, who is probably better known as a painter because for most of his life he could not afford stone for sculpting.

The limestone used for the "Tete" was one of several stone blocks that Modigliani and his friends would take at night from construction sites for the Paris Metropolitain.

What Modigliani and Giacometti had in common, Shaw added, was that "they're both inspired by the antique".