Through: This word identifies Silvanus as the amanuensis. An amanuensis is a person who writes down words as another person speaks or directs.
Silvanus: Silvanus is also known by the shorter name Silas. Both names refer to the same individual. He was a close colleague of Paul after the council in Jerusalem (Acts 15:40; 16:19; 17:10, 14–15; 18:5; 2 Corinthians 1:19; 1 Thessalonians 1:1; 2 Thessalonians 1:1).
We do not know how Silvanus later joined Peter in Rome. He may have traveled with Paul or followed him at a later time (Acts 27:1–28:31).