derived from the radical reformer MENNO SIMONS (1496-1561) http://en.wikipedia.org/wiki/Menno_Simons , a roman-catholic priest, who in 1536 joined the Anabaptists.
Back then, those had just failed to build a holy kindom in Münster ( city http://en.wikipedia.org/wiki/M%C3%BCnster) 1534/1535. Since they failed with that andwere facing quite a number of enemies afterwards, the leadership of Simons was inspirational to them.
His teachings about the baptism of Christians, the clerical discipline pacifism and the refusal of Christians, to participate any politics, did find great support in many communities. The number of followers grew especially in the 17th and 18th century ,esp. in Holland. From there it spread to other parts of Europe like the Ukraine.
Mennonites the contributed major achievements in agricultural and industrial development.
In late 19th and early 20th century Russian Mennonites were persecuted and emigrated to America and CANADA. Some settlements arose in South America too.
Today there are about 700.000 (1997) Mennonites in different places of the world, most of them in America, where some of the groups split up. They have now no real common teachings or way of life. BUT there is a wolrd-conference of Mennonites http://www.mwc-cmm.org/ which brought together a majority of the communities. Temporary Mennonite Journals support regular exchange of ideas.
C.J. Dyck: An Introduction to Mennonite History(1981)