
For three hundred years after the time of Jesus, there was no required Christian doctrine. Early Christians held many ideas about Jesus. Some thought he was a human teacher or prophet; some thought he was God; others thought he was more than a man but less than God.
But when the Roman Emperor Constantine I converted to Christianity, he convened a church council to settle the issue. Constantine wanted one uniform Christian doctrine, one creed agreed on by all Christians.
In 325 CE the Council of Nicea decided that Jesus and God were "of the same substance," equal and co-eternal. The issue continued to be debated throughout the fourth century, and the official position of the Church shifted depending on the beliefs of the current emperor. Under Emperor Constantius II, the Councils of Selucia and Rimini decided that Jesus was "of similar substance," not quite equal, to God. Emperor Theodosius I convened the Council of Constantinople in 381, which gave us the doctrine of the Trinity: one God who is three persons, God the Father, God the Son, and God the Holy Spirit. Theodosius persecuted everyone who disagreed. The Council of Chalcedon, convened by the Emperor Anatolius in 451, decided that Jesus was both 100% divine and 100% human, completing the doctrine of the Trinity.
And yet the terms "God the Son, "God the Holy Spirit," and "Trinity" never appear anywhere in the Bible. Jesus was a Jew, and Jews believe that God is one. If Jesus had believed himself to be the second person of the Trinity, and believed this doctrine to be important, one would expect that he would have made it central to his teachings, and we would see that reflected in the New Testament. But, as Harper's Bible Dictionary admits, "The formal doctrine of the Trinity as it was defined by the great church councils of the fourth and fifth centuries is not to be found in the New Testament."
The modern Unitarian movement was inspired by the publication of Michael Servetus' book, On the Errors of the Trinity, in 1531. Servetus was condemned to death by the Catholic Church in France, and he was burned at the stake by Protestants in Geneva, Switzerland, in 1553. His books caused great debate. By 1565 there was an organized Unitarian movement in Poland, officially named the Minor Reformed Church. An Italian, Fausto Sozzini (or Faustus Socinus), became the leader of the Minor Reformed Church, and so they are sometimes called "Socinians" after his name. The Polish Unitarian movement was wiped out in 1660, when the Socinians were given three choices: convert to Catholicism, leave Poland, or be executed.
Another Unitarian movement began in Transylvania in 1568, led by Ferenc David (or Francis David). Although David died in prison in 1579, the Transylvanian Unitarians, part of Romania's Hungarian-speaking minority, still survive. There are about 124 Unitarian Churches in Transylvania, with a membership of about 80,000.
The Transylvanian Unitarians are liberal Christians who believe in the teachings of Jesus of Nazareth and hold him up as an exemplar. They believe in the moral authority, but not the divinity, of Jesus. Unitarian Christians point out that according to the New Testament, Jesus said, "The Lord our God is the one Lord" (Mark 12:30). He also said, "My teaching comes not from myself, it comes from the one who sent me" (John 7:16). In Matthew 24:36 Jesus says that the Son does not know when the earth will pass away; only the Father knows. And in John 14:28 he says, "The father is greater than I." None of that sounds like someone who thought he was equal to God. The Apostle Paul wrote, "There is no God but the One" (1 Corinthians 8:4), and "God is supreme over Christ" (I Corinthians 11:3). Because of these biblical passages and many others, Unitarian Christians see Jesus as a human being chosen or anointed by God for a special purpose, but not a divine being.
A Unitarian movement dates to the 1600s in England. John Biddle (1615-1662), often called "the father of English Unitarianism," spent most of his adult life in prison because of his beliefs. In 1791 two Unitarian chapels in Birmingham, England, were burned during anti-Unitarian rioting. In the same incident, the home of Joseph Priestly, a scientist and Unitarian clergyman, was also destroyed. Priestly re-settled in the United States, where he helped establish Unitarian churches in Philadelphia and Northumberland, Pennsylvania, in 1794. In 1800 the church founded by the Pilgrims in Plymouth, Massachusetts, adopted Unitarianism.

By this time liberal Congregationalists in New England were being accused of being Unitarians. In 1819, a leading Boston Congregationalist, William Ellery Channing, accepted the Unitarian name and laid out the principles of "Unitarian Christianity": the simple unity of God and humanity of Jesus, the use of reason and scholarship when reading Scripture, and the ability of human beings to choose good over evil. Channing said, "The great hope of society is in individual character."
Ralph Waldo Emerson (1803-1882) served as a Unitarian minister before beginning his career as an essayist, poet, and lecturer. Emerson rejected supernatural miracles and encouraged people to seek God in nature. Theodore Parker, a follower of Emerson, suggested that Christianity as taught by the churches would fade away, leaving Jesus' pure religion and morality to last forever. Parker was active in the anti-slavery movement. Abraham Lincoln borrowed from Rev. Parker the phrase, "a government of all the people, by all the people, and for all the people," altering it slightly in his Gettysburg Address.
The Unitarians were among the first to ordain women to the ministry. Antoinette Brown Blackwell (1825-1921), the first woman to be ordained as a minister in the United States, started off as a Congregationalist but later became a Unitarian. In 1902 she helped establish the Unitarian Society of Elizabeth, New Jersey, becoming its first minister.
In the 20th century both the Unitarians and Universalists were influenced by the humanist movement, which sought natural, rather than supernatural, answers to religious questions. Unitarian ministers Curtis Reese (1887-1961) and John Dietrich (1878-1957) preached a positive agnosticism that they called naturalistic humanism. Dietrich wrote that our responsibility "is to put beauty in place of ugliness, good in place of evil, laughter in place of tears; to dispel error with knowledge, hatred with love; displace strife and contention with peace and co-operation."
Rev. John Haynes Holmes (1879-1964) was a prominent Unitarian minister and social activitist who helped found the NAACP and the ACLU, and was know for his opposition to war. Holmes also became a tireless advocate for the work and ideas of Mohandas Gandhi.
In 1961 the American Unitarian Association and the Universalist Church in America combined to form the Unitarian Universalist Association of Congregations (UUA). Today there are about 221,000 Unitarian Universalists in a little more than 1,000 UU churches and fellowships in the United States.
In March of 1965 more than 40 Unitarian Universalist ministers joined Rev. Martin Luther King, Jr., in the Selma to Montgomery voting rights march. One day after arriving in Selma, Unitarian Rev. James Reeb was murdered by white supremacists. After the death of Rev. Reeb, hundreds of other Unitarian Universalists joined the march. One of them, Viola Liuzzo, a Detroit housewife and college student, was also murdered by white supremacists.
Since 1970 the Unitarian Universalist Association has supported equal rights for lesbians and gays. The first legal same-sex wedding in the United States took place in 2004 in the Unitarian Universalist Association national headquarters in Boston, officiated by the president of the UUA.
Today, while we have no creed that members must agree to, we affirm the authority of reason and conscience, the freedom of religious expression, ethical living, and the importance of religious community. Our members hold a wide variety of religious beliefs. We agree on the value of the Golden Rule, "Treat others as you wish to be treated." We affirm that how you live your life is more important than belief in particular religious doctrines.
Rather than gathering around a creed or statement of faith that everyone must agree to, we gather around a covenant that affirms how we will treat one another on our spiritual journeys. One such covenant, written by the Rev. Alice Blair Wesley and based on the covenant of the Pilgrims, says: "We pledge to walk together in the ways of truth and affection, as best as we know them now or may learn them in days to come; that we and our children may be fulfilled, and that we may speak to the world in words and actions of peace and goodwill."