Does anyone have a source (Or explanation) about the origins of certain RC devotions such as the 9 First Fridays, Brown Scapular, Rosary, and Novenas? I am interested in knowing how this various practices went from no doubt peasant origins to becoming officially approved RC practices?
The First Fridays devotion arose from the private revelations to Saint Margaret Mary Alacoque in the 17th century regarding the Sacred Heart of Jesus.
The Brown Scapular was originally the work apron of the Carmelites (a.k.a. The Order of the Brothers of Our Lady of Mount Carmel). The word scapular comes from the Latin word meaning shoulder. Over time, the scapular became identified and a part of the regular habit of the Carmelites and for lay members of the Order to participate the scapular became smaller to be able to be worn with the laity's regular clothing. According to pious legend, Our Lady appeared to Saint Simon Stock with her promise of protection and intercession for all who die clothed in the scapular. The Brown Scapular is often associated with the Mantle of Mary.
The Dominican Rosary (there are many varieties of rosaries such as the Brigittine) came out of the Divine Office. The Monks were accustom to saying all 150 psalms every day. The laity wishing to participate in this laudable practice but lacking both the time and education (i.e., couldn't read) to pray the psalms they substituted 150 Hail Marys -- one for each psalm. Over time the Our Fathers were added and the Rosary was divided into 15 decades and to each decade some pious thought was attached. Again, over time, these thoughts settled onto the 15 mysteries known as the Joyful, Sorrowful, and Glorious. According to pious legend Our Lady appeared to Saint Dominic and charged him with preaching about praying of the Rosary.
Novenas go to the very birth of the Church. The first novena occurred during the nine days from Ascension Thursday to Pentecost -- the word novena comes from the Latin word for nine. Originally novenas were prayed for the coming of the Holy Spirit and it was the custom to pray a novena before Baptism or Confirmation. Over time, novenas were expanded to included praying to Saints and for particular petitions.
Does that answer your question?