The Teaching of the Twelve Apostles, commonly known as Didach?, which means "Teaching," is a brief early Christian treatise, dated by most scholars to the late first or early 2nd century A.D. The text, parts of which may have constituted the first written catechism, has three main sections dealing with Christian lessons, rituals such as baptism and Eucharist, and Church organization. It is considered the first treatise of the genre of the Church Orders.