The Religious Society of Friends began as a proto-evangelical Christian movement in England in the mid-17th century in Lancashire. Members are informally known as Quakers, as they were said "to tremble in the way of the Lord". The movement in its early days faced strong opposition and persecution, but it continued to expand across the British Isles and then in the Americas and Africa. During the 19th century, Friends in the United States suffered a number of secessions, which resulted in the formation of different branches of the Religious Society of Friends.