Anabaptists (meaning "re-baptizers") represent a radical Protestant tradition tracing its history to the 16th century C.E. reformer Ulrich Zwingli. The Anabaptists were distinct because of their assertion of the necessity of adult baptism, rejecting the infant baptism practiced by the Roman Catholic Church. They believed that true baptism required a public confession of both sin and faith, which could only be accomplished as an adult exercise of free will. Another defining characteristic of Anabaptists is their belief in the separation of church and state, and the concept that the church represents the community of saved. Even though the Anabaptist movement began in Zurich, Switzerland, it quickly spread to Moravia and throughout Germany. Many Anabaptists were persecuted in Europe, by both Roman Catholics and other Protestant groups, and most Anabaptist leaders were executed by the end of the 16th century C.E. However, in northern Germany and the Netherlands, pacifist Anabaptists rallied under the leadership of Menno Simons and survived the persecution. Menno's followers would eventually form the Mennonite tradition and become the only lasting Anabaptist tradition. The Mennonites continue to treasure the teachings of Menno, which include thoughts on pacifism, spirituality, and social ideas. Anabaptists, through the Mennonite tradition, are known for their separation from the world (including a refusal of military service), pacifism, radical discipleship, and simplicity of life.