During the Reformation in the 16th Century, Henry VIII declared the Church of England independent of the Roman Catholic Church with himself as its head. It was the result of many factors, some political and some theological, but it has given rise to a distinct form of Christianity, known as Anglicanism.
The Episcopal Church is a member of the worldwide Anglican Communion, the churches around the world that trace their roots to the Church of England, and maintain a “communion” with it, hence the name “Anglican.” the Episcopal Church is the American member of the Communion. The Episcopal Church in United States is the American member of the Communion. Most Anglicans now live in Africa.
The member churches of the Anglican Communion are joined together by choice in love, and have no direct authority over one another. The Archbishop of Canterbury, the head of the Church of England, is acknowledged as the spiritual head of the Anglican Communion, but while respected, the Archbishop does not have direct authority over any Anglican Church outside of England.