Throughout history, male artists have used muses for inspiration to create their best work.
And many such paintings have become more collectable simply because of the relationship between the artist and sitter.
That is the case with the subjects of two works snapped up this month for almost US$90 million (Dh330.5m) combined.
Pablo Picasso's take on his lover Marie-Therese Walter, a 1932 work called Femme Assise Près d'une Fenêtre (Woman Sitting Near a Window), which paints her with a large forehead, fetched $45 million at auction.
Helena Newman from Sotheby's was quoted as saying in the United Kingdom's Mirror newspaper that the 1932 work was a "stunning and monumental portrait".
Picasso met his muse in Paris in 1927 when she was 17, and they embarked on a long-term affair. The pair had a child together but Walter became jealous when Picasso took another mistress, Dora Maar (whom he also famously painted). It is said that the mistresses demanded that he choose between them. He told them to fight it out, and later called their wrestling match one of his "choicest memories".
Picasso supported Walter and his daughter, Maya, financially but they never married and Walter committed suicide four years after his death.
The subject of another painting that sold this month for $42.3m died in similarly tragic circumstances.
Jeanne Hébuterne (au chapeau), a portrait by the Italian artist Amedeo Modigliani a year before his death in 1920, was the leading lot at a Christie's impressionist, modern and surrealist sale.
Modigliani met Hébuterne, with whom he would have a child, towards the end of his life. He died as a result of tuberculous meningitis and complications brought on by substance abuse, leaving Hébuterne distraught. The day after his death she jumped out of a window, killing herself and their unborn second child.