How did Polycarp preserve the letters of St. Ignatius of Antioch?

St. Polycarp preserved the letters of St. Ignatius of Antioch by compiling a collection of them and sending them to the church of Philippi at the request of the Philippians.1

This collection likely included some, if not all, of the seven letters now recognized as genuine. By gathering and distributing these writings, Polycarp helped ensure their survival, allowing them to be known by later figures such as Eusebius. While the collection was later subject to 4th-century interpolations and the addition of forged letters, the original, genuine correspondence was eventually restored through 17th-century scholarship.1

Polycarp and Ignatius shared a close bond; Ignatius, who viewed Polycarp as a personal friend and younger colleague, addressed a specific letter of advice to him during his journey to martyrdom. In turn, Polycarp honored Ignatius’s legacy by holding him up as an example of patience and devotion to Christ.2