The encounter between Saint Simon Stock and the Virgin Mary is central to Carmelite spirituality and identity. According to tradition, Simon Stock, an English cleric and the prior general of the Carmelite Order, experienced this profound revelation while praying fervently in Aylesford, Kent. In this vision, Mary is said to have appeared with the Brown Scapular, a garment meant to symbolize the wearer's commitment to a life of virtue and fidelity to the teachings of Christ. She assured him that those who died wearing the scapular would receive her special protection, particularly from eternal damnation.

This event not only solidified the Carmelite Order's dedication to Marian devotion but also introduced the Brown Scapular as a significant sacramental in the Catholic Church. The story of Simon Stock and his vision became a cornerstone of Carmelite life, encouraging the faithful to wear the scapular as an expression of their trust in divine intercession. Over the centuries, the devotion to the Brown Scapular has expanded beyond the Carmelite Order, attracting numerous followers who see it as a means of grace and protection.

Critiques and doubts about the authenticity of Simon Stock's vision began to emerge during the Renaissance and the Reformation, as scholars and theologians scrutinized miraculous claims and the veracity of saints' experiences. Modern historians often approach such accounts with skepticism, focusing on the historical and social contexts in which these narratives were formed, which makes the event both a point of faith and contention.