Pablo Picasso and Mark Rothko are set to headline Sotheby's upcoming November auctions. The Nov. 5 Impressionist and Modern evening sale will see Femme à la fenêtre (Marie-Thérèse), a 1936 Picasso portrait of his mistress, head to the block. Nov. 13's contemporary art evening sale is highlighted by No. 1 (Royal Red and Blue), a 1954 Rothko canvas.

The Wall Street Journal reports that the Rothko comes from the collection of former Sotheby's president John Marion and his wife Anne. No. 1 (Royal Red and Blue) is one of eight works that Rothko created for his 1954 solo show at the Art Institute of Chicago.

In May of this year, Rothko's Orange, Red, Yellow (1961) sold for $86.8 million, a record for both the artist and post-war contemporary art in general. No. 1 is expected to fetch anywhere from $30-50 million. Orange, Red, Yellow carried a pre-auction estimate of only $45 million, and is two feet shorter than No. 1.

Meanwhile, the Picasso painting features the artist's famous muse, Marie-Thérèse Walter. Although the piece was made shortly after Walter gave birth to Picasso's daughter Maya in 1936, he was already beginning a new relationship with Dora Maar. Femme à la fenêtre remained in the artist's hands until his death. Pre-sale estimates put its price tag at $15-20 million.