The monograph is dedicated to the Slavic manuscript BAR Ms. Slav. 636 from the Library of the Romanian Academy in Bucharest, compiled in the Principality of Moldavia in 1557 during the reign of the Moldavian ruler Alexandru Lăpuşneanu (1552-1561; 1564-1568) and under the Suceava Metropolitan Gregory II, written by the hand of Hierodeacon Hilarion, in all probability in the Neamt Monastery. The manuscript is an occasion for the study of a cultural phenomenon related to faith, law and literature, characteristic of the two Romanian principalities, where during the Late Middle Ages a special synthesis of the literary heritage bequeathed by the South Slavs. The manuscript is a collection with mixed content of anthological sort, type of monastic encyclopaedia, with an unusually rich combination of texts of different genres and themes: legal, dogmatic, polemical, chronicle, apocryphal, and others. The aim of the authors is to study and publish the individual texts from the collection, revealing the overall message of the manuscript as a real verbal armament, a real spiritual sword in the fight against heresies for the salvation of human souls.