I have fully proclaimed the gospel of Christ: Paul was not saying that the work of sharing the gospel was finished in these regions. He meant that churches had been planted in enough major cities. These churches could now continue the work themselves. Paul’s own role of starting key and foundational churches had been completed.
from Jerusalem all the way around to Illyricum: This description covers the regions where Paul had planted churches, including southern Galatia, Asia Minor, Macedonia, and Greece. Illyricum was a Roman province along the Adriatic Sea. It lay northeast of Italy, in the area of modern-day Albania and Croatia.