Who is primarily known for composing letters to various churches?

Saint Paul is primarily known for composing letters to various churches, which are an essential part of the New Testament. His epistles address theological issues, moral guidance, and practical advice for the early Christian communities. These letters, such as Romans, Corinthians, and Galatians, not only provide insight into the teachings of Christianity during the formative years of the church but also reflect Paul's efforts to establish and strengthen relationships with believers across different regions.

In addition to his theological contributions, Paul's letters often respond to specific questions or challenges faced by the churches he wrote to, making them highly relevant for understanding early Christian doctrine and community life. His extensive correspondence laid the foundation for much of Christian theology and has significantly influenced both religious thought and academic study.

The other figures listed also played important roles in the early church, but they are not primarily recognized for writing letters in the same way Paul is. Saint Peter did write letters, notably the two epistles in the New Testament, but his contributions are quite limited compared to Paul's prolific writing. Saint John is known for his Gospel and the Book of Revelation, while Saint Stephen is noted more for his role as a martyr and deacon in the early church, rather than for letter writing.