From 1746 to 1759, West worked in Pennsylvania, mostly painting portraits. While in Lancaster, Pennsylvania, in 1756, West's patron, a gunsmith named William Henry, encouraged him to design a "Death of Socrates" based on an engraving in Charles Rollin's Ancient History; the resulting composition, which significantly differs from West's source, has been called "the most ambitious and interesting painting produced in colonial America".
Inspired by a true story, Invincible recounts the last 48 hours in the life of Marc-Antoine Bernier, a 14-year-old boy on a desperate quest for freedom.