Although the first congregation to call itself "Unitarian" in Britain dates from 1774, the roots of the Unitarian movement can be found in the sixteenth century in the Protestant Reformation in Europe and in the radical congregations in Britain in the seventeenth century which later called themselves Unitarian. There were in addition individual men and women with Unitarian views from much earlier times.

Unitarians are justly proud of their history of struggle against intolerance and persecution and of their distinguished contributions to religious and secular life, made over many centuries. Education, public health, literature, and political reform are fields with many distinguished Unitarian names.