Question: "Who were the Anabaptists, and what did they believe?"
Answer: Anabaptists are not a denomination, and it is unlikely that you will find any church named “First Anabaptist.” The name is more of a descriptive title than an organizational name. From the days of the apostles, there was one Church of Jesus Christ, with a single body of doctrine taught by the apostles and their successors. The various local churches preached repentance and confession of sins, along with baptism by immersion as an outward sign of the new life in Christ (Romans 6:3-4). Though under the authority of the apostles themselves as to doctrine, each church was independently governed by the leaders God placed in them. There was neither denominational hierarchy nor distinction of “us/them” within the various churches. In fact, Paul soundly rebuked the Corinthians for such divisions (1 Corinthians 3:1-9). When disputes over sound doctrine arose, the apostles declared God's teaching based on the words of the Lord and the Old Testament Scriptures. For at least 100 years, this model remained the standard for all churches.
Starting around A.D. 250, with the intense persecutions under Emperor Decius, a gradual change began to take place as the bishops (pastors) of certain notable churches assumed a hierarchical authority over the churches in their regions (e.g., the church of Rome). While many churches surrendered themselves to this new structure, there were a substantial number of dissenting churches that refused to come under the growing authority of the bishops. These dissenting churches were first called “Puritans” and are known to have had an influence as far as France in the 3rd century. As the organized (Catholic) church gradually adopted new practices and doctrines, the dissenting churches maintained their historical positions. The consistent testimony of the church for the first 400 years of its history was to administer baptism to only those who first made a profession of faith in Christ. Starting in A.D. 401, with the fifth Council of Carthage, the churches under the rule of Rome began teaching and practicing infant baptism. With the advent of infant baptism, the separatist churches began re-baptizing those who made professions of faith after having been baptized in the official church. At this time, the Roman Empire encouraged their bishops to actively oppose the dissenting churches, and even passed laws condemning them to death. The re-baptizers became known as Anabaptists, though the churches in various regions of the empire were also known by other names, such as Novatianists, Donatists, Albigenses, and Waldenses.
These Anabaptist congregations grew and prospered throughout the Roman Empire, even though they were almost universally persecuted by the Catholic Church. By the time of the Reformation, Martin Luther's assistants complained that the Baptists in Bohemia and Moravia were so prevalent, they were like weeds. When John Calvin's teachings became commonly known, many of the Waldenses united with the Reformed Church. From this point on, the various Anabaptist churches gradually lost their ancient names and many assumed the name Baptist, though they retained their historic independence and self-rule.
Who are the Anabaptists today? The most identifiable are the Hutterites, Mennonites, and Amish, though many modern-day Baptist churches would also identify themselves as the heirs of the Anabaptist traditions. The Hutterites, or more properly, the Hutterian Brethren, trace their history to 1528, when a group of Anabaptists fled persecution for their refusal to pay war taxes and formed a communal society in Austerlitz. Jakob Hutter, one of their first elders, was martyred in 1536. Along with pacifism, communal living is a keynote of Hutterite belief. The Mennonites were formed in Holland as a result of the severe persecution in Switzerland and Germany. The Anabaptists who fled to Holland were organized under the teaching of Menno Simons, a Catholic priest who aligned himself with the Anabaptists in 1539. Many Mennonites are identifiable by their plain dress and the head coverings worn by their women. The Amish trace their history back to a split of the Swiss and Alsatian Anabaptists in 1693, when Jakob Ammann felt that the Swiss Brethren were veering away from the strict teachings of Menno Simons and needed to enforce a stricter form of church discipline. The distinctiveness of the Amish is in their separation from the society around them. They shun modern technology, keep out of political and secular involvements, and dress plainly.
When asked how today's Anabaptists differ from other evangelical Protestants, one of their own said, “The Anabaptists see Jesus not only as Savior, but as Teacher, teaching them how to live their lives while on this earth. They believe that obedience to His commands is required; therefore, they try to live as He taught. Thus they are a separate people, following the hard narrow path to the Kingdom of God that Jesus taught and lived.” An emphasis of Anabaptist teaching is the Gospel of the Kingdom, which aims at the establishment of a place of love, joy, and peace in the Holy Spirit.