As far as can be ascertained from the earliest references, Simon Stock was an English Prior General, known for his holy way of life, who died about 1265 in Bordeaux in France. After his death, miracles were recorded by those visiting his tomb and during the 14th century a local cult developed in Bordeaux.
Around 1400, a separate legend emerged in the Low Countries of a "holy Simon" who had a vision of Our Lady, in which she appeared to him bearing the scapular and promised: "This is a privilege for you and your brethren: whoever dies wearing it, will be saved." Within a few years, the two accounts had been merged and Simon Stock, the Prior General, was credited with having the vision of Our Lady. The combined account quickly became elaborated with imaginary biographical details of Simon's life, such as his birth in Kent, his living for some years as a hermit in the trunk of a tree and his authorship of the Flos Carmeli, a beautiful Carmelite hymn to Our Lady (which is, in fact, found in the 14th century and hence predates the legend).
The cult of Saint Simon Stock and the scapular devotion spread rapidly throughout the 15th and 16th centuries and increasingly large numbers of lay persons were enroled in the scapular. Artists from all over the world have portrayed the scapular vision and examples are preserved in Carmelite churches throughout the Order. In the 16th century, the cult of Saint Simon Stock was made a part of the liturgical calendar for the whole Order, his feast being usually celebrated on 16th May. The feast was omitted in the recent reform of the liturgical calendar after Vatican II but has been now reintroduced.
Although the historicity of the scapular vision is rejected, the scapular itself has remained for all Carmelites a sign of Mary's motherly protection and as a personal commitment to follow Jesus in the footsteps of his Mother, the perfect model of all his disciples.