Romans 15:23-24

The apostle felt that the Christians in the areas he had evangelized were in a good position to carry on the propagation of the gospel in their territories. Consequently he believed that he could look to comparatively unreached fields farther to the west in what is now Europe (cf. Romans 1:11-12).

"Parts of Spain (which in the ancient world included all the Iberian peninsula) had been occupied by Rome since about 200 B.C.; but it was only in Paul’s lifetime that the Romans had fully organized the entire area." [Note: Moo, p. 900. See also The New Bible Dictionary, 1962 ed., s.v. "Spain," by A. F. Walls.]