The church in Rome. There are no records about who founded it, but we know that Christian faith was already being practiced among the Romans when Paul wrote this epistle.

Beyond this, there is no mention of Peter or any other apostle who may have taken the Word of God to that nation.

What we know is some Romans and Jews who lived in Rome were present on the day of Pentecost (Acts 2.10-11); therefore, it is possible that they took the Good New of Salvation to Rome.