James Martineau was a British religious philosopher influential in the history of Unitarianism.

Unitarianism, as a Christian denominational family of churches, was first defined in Poland-Lithuania and Transylvania in the late 16th century. It was then further developed in England and America until the early 19th century, although theological ancestors are to be found as far back as the early days of Christianity. It matured and reached its classical form in the middle 19th century. Later historical development has been diverse in different countries.