A portrait by Pablo Picasso has sold for almost $45-million at Sotheby’s in London.

The 1932 piece was called Woman Sitting Near a Window. It was a portrait of Picasso’s mistress, Marie-Therese Walter.

Piccaso referred to Marie-Therese as his “golden muse.” Several portraits of her have sold for millions of dollars each. She was the subject of his famous work, The Dream, also painted in 1932.

She was just 17 years old when their relationship began. Picasso was 45. They had a daughter together.