What are the Quakers and what impact

The Quakers are members of the Religious Society of Friends, which is a Protestant Christian denomination. Members of "the Friends" find unity in the belief that each human has the ability to experience the light within or "answering that of God in every one". Quaker missionaries arrived in America during the mid 1600s. Not knowing what part of American history your question pertains to, this is all the information I can provide.