What challenge did Christianity face during its early development?

During its early development, Christianity faced significant challenges, notably persecution from authorities for not worshiping the emperor. This was particularly true in the Roman Empire, where the emperor was often venerated as a god, and loyalty to the state was intertwined with religious practice. Christians, who refused to participate in these rituals as a matter of faith, were seen as subversive and unpatriotic. This refusal led to various forms of persecution, including social ostracism, imprisonment, and violence, particularly from the first century to the early fourth century.

The other challenges mentioned, such as a lack of followers or geographic isolation, do not capture the primary and immediate threat that persecution posed to early Christians. While there was resistance from other religions, it was the direct and systematic persecution led by Roman authorities that created the most dangerous environment for the growth of Christianity during its formative years.