Like most protestant religions, the Amish are divided into different groups, each of which complies with its own variations on the rules. These divisions happen, as usual, as a result of several doctrinal disputes. There are eight different divisions (also called subgroups or suborders) within the Amish people as a whole.
The most conservative suborder is called the “Old Order,” and it’s known to have the most strict rules involving dress. This one separated from the fellowship in the 1860s.
Sometimes the dispute that leads to divisions can be over trivial matters — for instance, the Troyer Amish withdrew from the larger community over a disagreement about hat brims. These differences related to belief can often result in bizarre forms of violence.