There are roughly 776 million Protestants worldwide - they make up over 40% of Christians. All have their origins, some more directly than others, in the 16th-century Reformation begun by Martin Luther.
Several important figures and social changes set the stage for the Protestant Reformation. Some forerunners were influential: Pope Gregory VII, Erasmus, John Wycliffe, and John Hus. In addition, the cultural and intellectual movements of humanism and nominalism influenced the reformers, and created a large audience for them.
Almost every branch of Protestantism can be traced back to a few founders. Most of them build, to at least some degree, on the work of Luther, Zwingli, and Calvin.
The Bible is the scripture and thus the most important set of writings for Protestant churches. Protestants claim to place the Bible as the ultimate authority for belief and practice. In addition, some Protestant churches have creeds (formal statements of belief), while others are non-creedal.
Historical scholarship on Protestant churches often reflects the theological perspectives of the people writing the scholarship. Recently three trends have emerged in study of the 16th-century origins of Protestantism: a focus on the medieval nature of the Reformation, attention to the lives of all classes of people at the time of the Reformation, and a debate about the meaning of changes to worship space inaugurated by the Reformers.
Two early developments in Protestantism were the challenge to the original reformers (Lutheran and Reformed) from the Anabaptists, and the spread of Protestantism from the European continent to England.
The Church of England and the Anabaptists continued to form sub-groups. Many came to the North American continent, sometimes because of persecution. In North America, the groups split even further.
Protestants played a role in most of the major colonial and imperial expansions of Europe and North America. They are implicated in positive and negative aspects of these conquests.
Protestant churches spread quickly in Europe, England, and America. When these regions became international powers, Protestant missionaries began to spread Protestant Christianity around the globe.
There are several important contemporary trends in Protestant denominations: most are experiencing numerical decline in Europe and North America, and growing in the global south; sects that split from each other in the 19th century are working together and sometimes reuniting; and the greatest growth globally is among Pentecostal and Charismatic churches.
Protestants believe that they are saved by God's forgiving grace. There are varying views among Protestants regarding such matters as the nature and extent of human participation in salvation.
Protestants believe in an all-powerful God who is perfectly good, loving, and holy. Most share the orthodox Christian view of Jesus as fully human and fully divine. Traditionally they believe in angels and the devil.
Human nature was created good, but through the fall became sinful, that is, fundamentally self-centered. The purpose of existence is to glorify God and live a life of service to God and others, which is possible only through God's free gift of spiritual life.
Protestants believe that suffering is a form of evil. Evil has come into the world through the work of Satan and through human rebellion against God. With other Christians, most Protestants recognize that we do not fully understand why specific instances of evil and suffering occur.
Traditionally, Protestants believe salvation is a gift of God, granted by faith. On the day of judgment, all people will be resurrected, those who have believed and trusted in Christ to a life of blessedness in the presence of God, and those who have rejected God's gift to a place of torment and separation from God.
Some Protestant traditions do not acknowledge sacred time other than Christmas and Easter. For many Protestants, however, sacred time is organized by a liturgical calendar that celebrates all the major events in the life of Jesus and in the early Church throughout the course of each year.
Protestants have largely rejected the use of images and statues in worship. They tend to have plainer, more austere worship spaces than Roman Catholics and Eastern Orthodox. There are differences, however, Lutherans and many Anglicans tending more toward the Catholic end of the spectrum than other Protestants.
The rituals of baptism and the Lord's Supper have been among the most important and contentious aspects of Protestantism. These practices embody important theological differences that distinguish the branches of Protestant Christianity (Reformed/Presbyterian, Lutheran, Anglican, Baptist, etc.).
Protestant daily life is shaped by the doctrine of the priesthood of all believers, which has implications for such matters as vocation and work ethic, and by the belief that salvation is by faith, which leads to an emphasis on nurturing personal piety.
Protestant symbolism tends to direct attention to the key doctrines of salvation by faith in the life, death, and resurrection of Jesus (as a gift of the Spirit), the priesthood of all believers (and so a downplaying of symbols setting aside ministers as different from others), and sola scriptura (the importance of the Bible).
Protestant churches do not have priests, but ministers. This is because all Christians have equal status in God's eyes and direct access to God. There is no special class of Christians. At the same time, some people's "gifts" are well suited to the tasks of preaching and pastoral care, and these people are "called" to the ministry.
Protestantism began with attempts to reform the Church so that it would be in accord with the principles of morality and community found in scripture.
Protestants base their moral thought and action on the Bible first and foremost. Corresponding to the theological diversity of Protestantism, there is a diversity of views on moral issues.
There is a spectrum of Protestant views of the Kingdom of God, from those who believe that it is a this-worldly possibility, to those who believe that it will only be realized in a not-yet-arrived future, to those who believe that it is only a heavenly reality.
Protestant denominations are divided on questions of gender and sexuality. European churches tend to be liberal. Asian, South American, and African churches tend to be conservative. American churches have become increasingly fractured in recent decades.