In 1926, customs officers looked at a gleaming bronze sculpture and declared it an industrial machine part, slapping it with a heavy commercial tax. By refusing to see a bird in that polished metal, they put the very definition of art on trial.

This episode traces the journey of Constantin Brancusi, the patriarch of modern sculpture, from herding sheep in the Carpathian Mountains to the center of the Parisian avant-garde. We explore how a peasant boy who mastered anatomy then deliberately unlearned reality forced a superpower's legal system to recognize abstract thought as tangible art.

• How he hand-built a working violin from scrap wood, altering his entire trajectory
• Why he quit Rodin's studio after two months: 'nothing can grow under big trees'
• The scandal of Princess X and the landmark Brancusi v. United States ...