Brancusi's ability to find the essential form in individual features is clearly seen in this group of works. The impetus is the traditional portrait bust, as can be seen in A Muse (1912) which began as a portrait of Renée Franchon, a friend who also posed for the Sleeping Muse. Another friend, Margit Pogany, was the inspiration for Mlle Pogany II (1919), one of the sculptures that came to epitomise Brancusi's work.

The most radical of these works is the mysterious Princess X (1915). A photograph survives of the first version of this sculpture, in which a woman arches her neck to catch a glimpse of herself in a mirror. The neck is exaggerated in order to convey the selfawareness of this gesture. Dissatisfied with this version, Brancusi carved back the superficial details. The head became an ovoid on an arching neck and the supporting hand is reduced to a pattern.

He showed this sculpture in New York, but when the bronze version was exhibited in Paris in 1920 it was banned - to Brancusi's apparent bewilderment - as being deliberately phallic. It was only reinstated as a result of a campaign to support his freedom of expression.