What group vowed to break away entirely from the Church of England?

The group that vowed to break away entirely from the Church of England is the Separatists. Separatists believed that the Church of England was beyond reform and that true Christians needed to separate themselves completely from this church to worship freely and authentically. They sought to establish their own independent congregations that adhered to their interpretations of Christianity, distancing themselves from the practices and doctrines dictated by the established church.

In contrast, the Puritans also sought to reform the Church of England but aimed to purify it from within rather than create separate churches. Anglicans are the established members of the Church of England itself, while Quakers, known for their unique beliefs and practices, were also not seeking to break away from the Church of England in the same fundamental way as the Separatists. Thus, the distinct mission of the Separatists to completely remove themselves from the Church is what makes this choice the correct one.