All of the Apostle Paul's letters that were included in the New Testament.
Paul the Apostle is considered one of the most influential figures in the spread of Christianity, and wrote a bunch of letters that are more formally known as the "Pauline Epistles".
Paul was originally a Jewish person, and a persecutor of early Christians, until he underwent a mystical experience that he described as a revelation of Christ. His letters, written to various Christian communities, address theological concerns, ethical questions, and practical issues faced by these early churches. Paul and these letters are largely considered responsible for the spread of Christianity from it's Jewish roots to the "Gentiles", or the non-Jewish.
Seven of these letters are believed by scholars to be authentic, composed between approximately 50 and 62 CE, making them some of the earliest Christian writings we have at all. Three of these letters are debated, while most scholars agree the Pastoral letters, besides Philemon, are pseudepigrapha. These letters make up the majority of the New Testament besides the Gospels- Paul is the most featured writer by far in the New Testament.
Paul's writings cover a range of topics, including the relationship between the Jewish and Gentile groups in the emerging Christian communities and the transition in theology between the traditional Jewish and new Christian ideas. They played a crucial role in early Christian theology and provide glimpses into controversies that arose within these communities, showing the diverse beliefs and practices of early Christians as they developed in the first century CE.
Open letters written by the Apostle Paul to churches and whole groups of people.
Unlike the Church Letters, these are the few letters of Paul that were written to specific people with specific advice.