Christian Fathers were influential figures in the early history of Christianity. They played several important roles in the development and establishment of Christian theology, doctrine, and practice. Here are some of the key things that Church Fathers did:

Doctrinal Development: Church Fathers engaged in theological debates and discussions that helped to shape the core beliefs of Christianity. They clarified and defended key doctrines, such as the nature of the Trinity, the divinity and humanity of Jesus Christ, and the nature of salvation.

Apology and Defense: Many Church Fathers wrote apologetic works to defend Christianity against various philosophical, theological, and cultural challenges. These writings aimed to provide rational explanations for Christian beliefs and to counter accusations against the faith.

Biblical Interpretation: Church Fathers were instrumental in developing early methods of biblical interpretation. They wrote commentaries on the Scriptures, explaining their theological significance and providing guidance on how to understand and apply the teachings of the Bible.

Ecclesiastical Organization: Church Fathers contributed to the organization and structure of the early Christian Church. They participated in debates about the authority of bishops, the role of councils, and the proper governance of the Church.

Formulation of Creeds: The Church Fathers played a crucial role in formulating creeds and statements of faith. The Nicene Creed, for example, which outlines the core beliefs of Christianity, was developed through the contributions of these early theologians.

Spiritual Writing: Many Church Fathers wrote letters, sermons, and treatises that provided guidance on Christian living, ethics, and spirituality. These writings continue to be valuable resources for understanding the moral and spiritual aspects of the faith.

Response to Heresies: Church Fathers addressed various heresies and theological deviations that arose in the early Christian period. They engaged in theological debates and councils to define orthodox beliefs and counter erroneous teachings.

Preservation of Early Christian Thought: Through their writings, Church Fathers preserved the theological and doctrinal developments of the early Christian era. Their works provide insight into the beliefs and practices of the early Church.

Establishment of Christian Tradition: The teachings and writings of Church Fathers contributed to the establishment of foundational Christian traditions that continue to shape various branches of Christianity to this day.

Overall, the Church Fathers played a critical role in laying the groundwork for Christianity as it developed from its early beginnings into a distinct religious tradition. Their writings and contributions continue to be studied and revered by theologians, scholars, and believers alike.