Universalism is a basic concept in which its adherents believe that there is complete salvation. Everyone will reach heaven after death eventually. Salvation does not discriminate by creed, belief, race or any other factor. Universalism has its roots in Christianity, but it is a heretical doctrine. That means that this belief in universal salvation, i.e., salvation for all, is not espoused by the traditional Church, which was Catholic.
What came to be known as traditional Christianity teaches that heaven is reserved for a small minority of people; the vast majority of people (non-Christians most notably) will not reach heaven at all. So, what did the earliest Christians believe and why is it important to our understanding of Universalism?
After Christ's death, between 27 A.D. and 36 A.D., the early Church that would eventually bear his name was splintered and scattered. The Apostles, either through fear for their lives or whatever else, moved to various parts of the ancient world. Each of these Apostles took different beliefs and understanding of Jesus' message.
Eventually, there would be power jockeying among these splinter sects. What came to be known as the "one, true, religion" was what we refer to as traditional Christianity, i.e., Roman Catholicism. "True Christians" held that Christ was divine and they believed in the trinity - Father, Son and Holy Ghost. The religion they described as universal in the Nicene Creed was, in fact, NOT. However, there were a great many believers stemming back from the first century A.D., who maintained that God would not deny his grace to so many. Heaven was meant for all of us, not just some of us.
Depending upon who held power in the early Church, this doctrine of Universalism could find favor or lead its believers to serious harm. By the end of the 6th century, the Early Church, which had become the state religion of the Roman Empire, was condemned publicly under the Fifth General Council. Of course, the doctrine didn't die, despite the persecution that followed.
Manicheans, Waldensians and Cathars all believed that salvation was equal opportunity. They paid dearly for this belief. In fact, the doctrine of universalism was widely regarded as an underground doctrine from the 6th century to the time of Martin Luther and the Protestant Reformation in the 16th century.
From that time on, universalism was reevaluated by many of the Protestant-based religions and took root, especially in the more liberally-focused Christian sects. As people's relationship to and understand of God has matured, many have Universalists have come to maintain that everyone one of us has the ability to have a loving and positive relationship with God. A belief in Christ is not necessary for that to occur.
Universalist sects made their way across Europe and took root in England as early as the eighteenth century. Universalist principles, as a result, were brought over to the New World, which would eventually be known as the United States. Universalism existed in the US for almost two centuries on its own. It took root most commonly in rural, interior sections of New England, and specific localized areas throughout the Mid-Atlantic and the South.
Universalism challenged its adherents to embrace those who were marginalized by society. Universalist congregations were also the first denomination to admit female ministers when, in 1863, Olympia Brown, was ordained. Universalism was also an evangelical faith. Therefore, Universalists were encouraged to share their beliefs with others.
They also were urged to perform social service. Universalists, because they believed in the equality of all before the Deity, became involved in issues such as abolition, and prison reform. Universalists believed in breaking the bonds of oppression whether they are race, disability, situation, socioeconomic status or the like.
It was also in the nineteenth century when Universalism became less of a Christian-based doctrine and more of a faith-based doctrine. Texts from other religions were incorporated into the faith. Around this time, the Universalists and the Unitarians came to realize that, by merging the two religions, which weren't very different, they could have a stronger church in numbers and in action.
Unitarians did not adhere to the belief in a trinity. They didn't see God as Father, Son and Holy Ghost. Jesus was a man who was sent by God, but he wasn't of God in any different way than anyone else was. God exists in one entity; not three. This doctrine was also very controversial (and, in many ways, still is). Unitarianism took root in Transylvania, a province of Romania which is known mostly for its link to Dracula and vampire lore, of all places. This occurred in the 16th century. The religion made its way to the New World, by way of England, most likely, and had a similar evolution to the one experienced by Universalism.
By the middle of the 20th century, Universalism and Unitarianism merged into Universalist Unitarianism. In 1961 the Unitarian Universalist Association was formed. Today, it helps to manage over 1,000 liberal congregations in the United States. Of course, there are UU, which is the common abbreviation for Universalist Unitarianism, congregations all over the world as well. Modern UUs recognize their rich cultural and religious history. They try to bring together elements from many different faiths, including Jewish, Christian, Muslim, Nature-based religions and many others. UUs are not exclusive; but rather, inclusive and inquisitive.
They tend to be intelligent people who try to live their lives in an ethical and socially responsible manner. Personal experience, conscience and reason are the true authorities in UU congregations. It's a creedless faith in which anyone can join. However, it is not an easy faith to live by because it requires action and proposes inclusion of many diverse experiences. Universalist Unitarianism is not easy to define. What it once was is not what it has become. By the same token, what it is in one congregation or to one Universalist Unitarian can differ from another.