Benedictine Abbot Rupert of Deutz, perhaps the most prolific Biblical commentator of the twelfth century, wrote a commentary on the Canticle of Canticles which he called the “De Incarnatione Domini”. Rupert was the first ever to give an entirely Marian interpretation to the Song of Songs in which he identifies the bride of the Canticle with the Virgin Mary. Rupert applies to Mary the title of Magistra Apostolorum (“Teacher of the Apostles”). However, in Medieval Latin, the word Magistra could mean far more than a teacher. It could also refer to “Mother”, “Queen”. The usage of this title stems from an early Church tradition which held that after the Resurrection, having, from the cross, made her their Spiritual Mother, Jesus left his Mother on earth to be with the Apostles as their mother and teacher. All that Mary had stored up and pondered in the silence of her maternal heart during Jesus’ time on earth was later revealed after Pentecost when she began to explain to the Apostles all the mysteries concerning her divine Son that she had been pondering. This book will be of interest to students and all others interested in Scripture studies, Theology, Mariology and Medieval studies.