Final answer:
The teachings of Jesus were spread by his apostles, particularly Paul, who was influential in the growth of Christianity within the Roman Empire. As more people, especially Gentiles, followed Jesus's message, Christianity became distinct from Judaism. Important events such as Emperor Constantine's conversion and the recognition of Christianity as a lawful religion contributed to its establishment and spread.
Step-by-step explanation:
Following the death and resurrection of Jesus, his followers known as the disciples or apostles wrote down and spread his teachings. One man, Paul, originally named Saul and a former Jewish leader, traveled throughout much of the Roman Empire, and attracted many new followers to Jesus's message. As more Gentiles (non-Jews) adopted the idea of Jesus as the Messiah, Christianity became a religion distinct from Judaism.
Christianity rapidly spread through the Roman Empire and was especially embraced by slaves, who were attracted to its message of forgiveness, an all-powerful God's love, and eternal life after death. Despite initial persecutions by the Romans, the religion grew in numbers and influence. The teachings of Jesus, which include a call for devotion to God, promise salvation for those who seek forgiveness, were captured in the writings of the New Testament. Paul's evangelistic work and his interpretation of Jesus's crucifixion as part of a divine plan to absolve human sin played a crucial role in establishing a unified Christian doctrine.
The early centuries of Christianity saw significant debates and varied interpretations of Jesus's teachings, with important contributions from various early Christian figures in defining the faith's core beliefs and practices. Christianity's recognition as a legally acceptable religion, and later as the state religion under Roman Emperors like Constantine and Theodosius, was instrumental in its growth and establishment.