Jakob Ammann (1644-~1730) — Swiss Anabaptist pastor whose name all Amish in the world carry.
Context
Anabaptists were radical Protestants who believed baptism should be conscious (not infant). For this, both Catholics and Lutherans persecuted them. By the 1690s, Anabaptists in Switzerland and Alsace lived in hiding, on remote farms.
The 1693 Schism
Ammann believed the community had become too worldly. His demands: strict discipline (Meidung — shunning the excommunicated), plain dress, beards for men, rejection of worldly customs. Senior leaders disagreed. Ammann excommunicated them. They excommunicated him. The split became permanent.
Result
Ammann's followers = Amish. Those who stayed = Mennonites. The difference persists 330 years. Mennonites drive cars and use electricity. The Amish do not.
Personality
Little is known about Ammann himself. No portraits (Amish don't draw people). No memoirs. Even his death date and place are unknown. A man who created an entire people — and dissolved into them.