Early ChristianityEarly Christianity, or Paleochristianity, describes the historical era of the Christian religion up to the First Council of Nicaea in 325. Christianity spread from the Levant, across the Roman Empire, and beyond. Originally, this progression was closely connected to already established Jewish centers in the Holy Land and the Jewish diaspora. The first followers of Christianity were Jews who had converted to the faith, i.e. Jewish Christians. Early Christianity contains the Apostolic age and is followed by, and substantially overlaps with, the Patristic era.
ProtestantismProtestantism is a branch of Christianity that follows the theological tenets of the Protestant Reformation, a movement that began in the 16th century with the goal of reforming the Catholic Church from perceived errors, abuses, and discrepancies. Protestantism emphasizes the Christian believer's justification by God in faith alone (sola fide) rather than by a combination of faith with good works as in Catholicism; the teaching that salvation comes by divine grace or "unmerited favor" only (sola gratia); the priesthood of all believers in the Church; and the sola scriptura ("scripture alone") that posits the Bible as the sole infallible source of authority for Christian faith and practice.
Apostles in the New TestamentIn Christian theology and ecclesiology, the apostles, particularly the Twelve Apostles (also known as the Twelve Disciples or simply the Twelve), were the primary disciples of Jesus according to the New Testament. During the life and ministry of Jesus in the 1st century AD, the apostles were his closest followers and became the primary teachers of the gospel message of Jesus. There is also an Eastern Christian tradition derived from the Gospel of Luke of there having been as many as seventy apostles during the time of Jesus' ministry.