Correspondence of Paul and Seneca
The Correspondence of (or between) Paul and Seneca, also known as the Letters of Paul and Seneca or Epistle to Seneca the Younger, is a collection of letters claiming to be between Paul the Apostle and Seneca the Younger. There are 8 epistles from Seneca, and 6 replies from Paul.
Source: Wikipedia — Correspondence of Paul and Seneca (CC BY-SA 4.0)