William Robertson (1705–1783) was an Irish clergyman, known as a theological writer and schoolmaster. Theophilus Lindsey wrote of Robertson as "the father of unitarian nonconformity".

Theophilus Lindsey was an English theologian and clergyman who founded the first avowedly Unitarian congregation in the country, at Essex Street Chapel. Lindsey's 1774 revised prayer book based on Samuel Clarke's alterations to the 1662 Book of Common Prayer inspired over a dozen similar revisions in the succeeding decades, including the prayer book still used by the United States' first Unitarian congregation at King's Chapel, Boston.