The seventh of eight children, James Martineau was born in Norwich, England, where his father Thomas (1764–1826) was a cloth manufacturer and merchant. His mother, Elizabeth Rankin, was the eldest daughter of a sugar refiner and a grocer. The Martineau family were descended from Gaston Martineau, a Huguenot surgeon and refugee who had settled in Norwich.
Martineau was educated at the Norwich Grammar School and on leaving he was apprenticed to a civil engineer at Derby, where he acquired “a store of exclusively scientific conceptions,” but also began to look to religion for mental stimulation. At this point decided to train as a train for the Unitarian ministry and entered Manchester College which was then at York. As a qualified Unitarian minister he started his ministry in Dublin, 1828, and married Helen Higginson in December, 1828. In the summer of 1832 he moved from Dublin to Liverpool where he was a great success. He was at one time President of the Philosophical Society and joined the staff of Manchester College in 1840, at the time of its return to Manchester where for 45 years he was lecturer and Principal, responsible for training ministerial students.
Martineau, though always calling himself a Unitarian, would never allow his congregation to be called so, insisting that they were individual thinkers agreeing only on the Universality of God. He hated controversy, above all about religion, regarding it as the antithesis of Christ’s teaching.
To Martineau, to be a Christian was to follow where Christ led. He wished to avoid theological speculation about Christ’s person and concentrate on his teachings. Nevertheless, to adopt the religion of Jesus was not to give preference to earliest Christianity. One form of Christianity was not better because it was older, he said. Martineau gladly used the methods of historical criticism to understand the Bible. He rejoiced in the light that science shed on theology. He investigated and spoke well of non-Christian religions. He wrote that he wanted “Christianity purified of superstitions, a Church intent only on Righteousness, and a Social habit of justice and charity to all men.”
Martineau was involved with Unitarian affairs nationally, e.g. the passage of the Dissenters’ Chapels Act, the opening of the universities to dissenters without doctrinal tests, and the decision to move Manchester College to London (associated with University College London).
Martineau’s writings emphasized the individual human conscience as the primary guide for determining correct behaviour. His writing on religion especially ‘Types of Ethical Theory (1885)’, ‘A Study of Religion (1888)’, and ‘The Seat of Authority in Religion (1890)’ were widely regarded as important works and helped shape Unitarian thinking.
Many of the Martineau’s were active in Unitarian causes (he is the brother of Harriet Martineau), so much so that a room in Essex Hall, the headquarters of British Unitarianism, was eventually named after them.