The Sacramentarium Leonianum is a book written by Charles L. Feltoe that contains a collection of prayers and liturgical texts used in the early Christian Church. The book is named after Pope Leo I, who was known for his contributions to the development of Christian liturgy. The texts in the book are written in Latin and date back to the 5th and 6th centuries. The Sacramentarium Leonianum includes prayers for various occasions, such as baptism, confirmation,...