Different sects of Christianity may perform various different kinds of rituals or ceremonies on a convert in order to initiate them into a community of believers. The most commonly accepted ritual of conversion in Christianity is through baptism, but this isn't universally accepted among Christian denominations. A period of instruction and study almost always ensues before a person is formally converted into Christianity, but the length of this period varies, sometimes as short as a few weeks and possibly less, and other times, up to as long as a year or possibly more.
Most mainline Christian denominations will accept conversion into other denominations as valid, so long as a baptism with water in the name of the Trinity took place, but some may accept a simple profession of faith in Jesus as Lord as being all that was needed for true conversion. Other Christians may not accept conversions performed in other denominations and certain communities may be discriminated against as heretical. This is most true for many nontrinitarian sects, which many mainstream Christian denominations (Catholic, Orthodox, and Protestant) reject as having valid forms of conversion. Consequently, many nontrinitarian sects spiritually isolate themselves in that they may only consider their conversions valid and not those of mainstream Christianity.
Social scientists have shown great interest in the Christian conversion as a religious experience that believers describe as strengthening their faith and changing their lives. Christianization, defined as the "reformulation of social relations, cultural meanings, and personal experience in terms of (commonly accepted or supposed) Christian ideals," should be distinguished from conversion. Christianization is the broader cultural term, and typically has involved efforts to systematically convert an entire continent or culture from existing beliefs to Christianity.
Christian denominations vary on the exact procedures of conversion. More traditional Christian groups such as the Catholic Church, the Orthodox Church, Lutherans, Anglicans, Methodists, and some Reformed Christians consider the sacrament of baptism in the name of the Trinity to be the moment of conversion. All of these groups teach the doctrine of baptismal regeneration, that is, once baptized, all past sins, including original sin, are washed away and a person becomes justified before God. Through baptism, one is incorporated into the body of believers, called the Church, and may rightly be considered a Christian. Some of these groups may also administer other sacraments in the process of conversion such as confirmation. Evangelical Christians, like Baptist, and Pentecostals, do not believe baptism is necessary for salvation and conversion, but only that a profession of faith is enough. Christians also differ on how old someone must be to convert. More traditional groups of Christians believe conversion is not restricted to age, and tend to baptize infants. Evangelical Christians do not baptize children because they see conversion as a deeply personal decision.
Conversion has been used as a tool by imperial powers during the peak of slave trade & colonization of Asia & Africa. Even today it remains to be one of the greatest causes for social conflict in many countries.