History of Jehovah's Witnesses
Jehovah's Witnesses originated as a branch of the Bible Student movement, which developed in the United States in the 1870s among followers of Christian Restorationist minister Charles Taze Russell. Bible Student missionaries were sent to England in 1881 and the first overseas branch was opened in London in 1900. The group took on the name International Bible Students Association and by 1914 it was also active in Canada, Germany, Australia and other countries. The movement split into several rival organizations after Russell's death in 1916, with one—led by Russell's successor, Joseph "Judge" Rutherford—retaining control of both his magazine, "The Watch Tower", and his legal and publishing corporation, the Watch Tower Bible and Tract Society of Pennsylvania.
Jehovah's Witnesses splinter groups
Scholars estimate that during the Nazi regime, about half of all Jehovah's Witnesses in Germany were incarcerated in prison or concentration camps, where they were exposed to "sadism marked by an unending chain of physical and mental tortures, the likes of which no language in the world can express." At the time, they were represented by several geographical Bible Students Associations, each of which considered itself affiliated with the Watch Tower Society despite little contact with their US headquarters in Brooklyn. When contact was re-established, a minority of German Jehovah's Witnesses either preferred their autonomy or disagreed with the doctrinal changes that had occurred in the meantime. Some disassociated themselves from the Watch Tower Society and some individual members established contact with non-Jehovah's Witness Bible Student groups.