Mennonites are members of a Christian denomination founded by the disillusioned Dutch priest Menno Simons way back during the Reformation. Today there are some one million Mennonites worldwide. In the United States, Mennonites are most common in Pennsylvania, Ohio, Indiana, Virginia, Iowa, Nebraska, and Kansas.
Menno Simons built on the Anabaptist tradition, which began in Switzerland in 1525 when a bunch of people decided that the baptisms they'd received as infants weren't all that meaningful after all, and that they'd like to have another go. Anabaptist literally means 're-baptiser,' which pretty well describes what the movement was all about. Under the Lutheran and Catholic state churches of Europe, everyone was baptised into the church at birth so that children would enter life cleansed of original sin. The Anabaptists contended that, since baptism was a symbol of an individual's commitment to follow Christ, it should be done only to consenting adults. They believed that, while everyone was born into sin, children are in a state of grace until old enough to make an informed decision to follow or reject the faith.
In other areas, Anabaptists attempted to return to the practises of the earliest Christians. Thus they practised pacifism, studied the Bible and worshipped together in each other's homes, and in some cases even formed communes to share their possessions. The state churches didn't much like this challenge to their authority, and so persecuted and killed Anabaptists, who, being pacifists, were rather easy targets. The movement persevered, though, and is still strong today. Modern denominations which grew from the original Anabaptist tradition include the Church of the Brethren, the Brethren in Christ, the Mennonites, the Amish, and the Hutterites.
The Mennonite Church, as mentioned before, was founded by Menno Simons, a Dutch priest who joined the Anabaptist movement. The Mennonite Confession of Faith is a pretty long document, but it may be briefly said that, like all Christian denominations, Mennonites believe in the sovereignty of God over his creation (ie, everything), the redeeming power of his son the risen Christ, the powerful presence of the Holy Spirit, and the divine inspiration of the Bible. What sets Mennonites apart are their Anabaptist beliefs that the decision to follow Christ can only be made by a consenting adult and that Christians are called to take literally the command to love their enemies given to them in the Sermon on the Mount (See the Gospel of Matthew, Chapter 5, Verses 43 to 48). To put it another way, Mennonites believe that Christians are called to do their best to imitate Christ in all areas of their lives, and thus try to live in peaceful service to all.
Pacifism, probably the most radical of Mennonite beliefs, has meant very different things to members of the church over the years. In the first years of the movement, Anabaptists (and later Mennonites) practised pacifism most visibly by refusing to use violence to defend themselves against persecution, taking literally Christ's words;
But I tell you, do not resist an evil person. If someone strikes you on the right cheek, turn to him the other also.
- Matthew, Chapter 5, Verse 39, New International Version
... and following the Saviour's example of willing death on the Cross. One particularly beautiful story from this period concerns Dirk Willems, who after escaping prison turned back to rescue one of his pursuers when the man fell into an icy pond. Willems was subsequently arrested and burned to death for his 'heresy'. The reformer Martin Luther, who founded one of the state churches that persecuted the Anabaptists, once wrote mockingly of Anabaptist prisoners who refused to slap at the very fleas that bit them.
Anabaptists did depart from this core belief on one notable occasion, when a group of them forcefully took control of the German city of Muenster. They hoped, misguidedly, to establish a millennial 'New Jerusalem', and instituted a form of communism and polygamy before they were defeated. One of Menno Simon's major contributions was to help institute a return to Anabaptism's original peaceful theology.
Fleeing persecution in Europe, many Mennonites moved to America. Before the 20th Century, North American Mennonites usually considered that living peacefully meant more-or-less hiding from the rest of the world and hoping that they weren't noticed whenever there was a war. There are a few inspirational stories of the Mennonite witness for peace during this period, though, including one about a Mennonite gunsmith who refused to make weaponry for the Continental Army during the American Revolution.
Since the turn of the 20th Century, however, Mennonites have increasingly turned to the more active pacifism modelled by Mahatma Gandhi and Martin Luther King, Jr (Mennonites tend to be more comfortable quoting the latter than the former). This has led the church to pursue more active peacemaking and service roles in countries across the globe. During World War II, for instance, Mennonites chose to participate in alternative service as medics, forest fire fighters, and even experimental test subjects. As a rule, Mennonites continue to conscientiously object to the draft, and some even withhold their taxes to avoid funding the military.
Mennonites are saddled with quite a lot of cultural stereotypes. Some corrections to popular perception are therefore in order. First, Mennonites are not Amish. The Amish split away from the Mennonites (rather than the other way round as is often assumed) to pursue a life of strict separation from the world. Second, Mennonites are not necessarily against technology in any particular sense. While some of the more conservative sects still paint their bumpers black (or even drive buggies) and make a point of dressing differently to set themselves apart from the world, at least one Mennonite has now contributed to h2g2; most are as up-to-date and/or well-dressed as the next person. Whether this is a good thing given the Mennonite ideals of simplicity and separation from the world is up for debate (or 'dialogue,' as Mennonites would have it).
It is true, however, that the Mennonites of North America love few things more than a church fellowship meal in which the dishes feature far more carbohydrates than vitamins, that they can be real tightwads (Mennonites usually prefer to call this 'good stewardship'), and that they will split off to form their own denomination at the drop of a hat. Recently the two largest Mennonite denominations in the United States merged to form Mennonite Church USA, an event that is almost certainly the first of its kind in the church's history.
North American Mennonites in particular are fond of good, old-fashioned four-part harmony hymns, and sing them at all opportunities. It is not unusual for non-Mennonites to know more about the quality of the church's music than their more significant theological positions.
Since Mennonites are a relatively small group, and in many cases attend a small collection of private Mennonite-run schools and colleges, they often engage in what they call the 'Mennonite Game,' which is essentially the act of drawing connections between themselves and other Mennonites. The standard protocol is for two Mennonites who are meeting for the first time to cast about for potential connections until something, however tenuous, is established. For instance, Mennonite A might, upon learning that Mennonite B attended Bethany High School in Goshen, ask Mennonite B whether he or she knows any of Mennonite A's relatives who live in Goshen. Because of the aforementioned common geography, schools, and activities Mennonites hold, connections are not at all difficult to discern, with the result that most Mennonites can find relatives in almost any large church-related gathering.
Mennonites have a fairly good presence on the greater Web. Check out:
Mennonite.net is more-or-less the central Mennonite web site.
Mennonite Central Committee is a relief, service, and peace agency of the North American Mennonite and Brethren in Christ churches.
Mennonite Weekly Review is one of the larger Mennonite publications in North America.