Romans 15:24 describes Paul's desire (prediction?) of going to Spain. Many scholars believe that there is strong evidence in favor of Paul having visited Spain. They point out that it is reasonable to say that Paul did visit Spain for the following reasons:
It was a possibility time wise (e.g. see R.C.H. Lenski's commentary here on page 480).
The church was large and well-organized at an early date.
The plans of Paul included a visit to Spain.
Early documents indicate that such a visit was made.
Local Spanish traditions speak of a visit by Paul.
However, some argue that to evangelize Spain to the extent we see at such an early date, Paul would have worked with other people. Spain was very closely linked to Rome and scholars have made a conjecture that some of the converted Pretorium guards or equites that were with Peter in Rome may have had connections in Spain where Paul traveled.
In The Clementine Gospel Tradition by Dennis Barton, the following comments are made:
Clement of Alexandria (c. 150-215) was a pupil of Pantoris, the first great Christian teacher at Alexandria in Egypt. Clement records that he himself had travelled widely, meeting and listening to ‘truly notable men’ from all over the Roman Empire (EH 5, 11).
In his Adumbrationes in Epistolas Canonicas, Clement commented on 1 Peter 5, 13. As Eusebius did not copy the full quotation, we are using here the Latin translation by Cassiodorus:
Mark, the follower of Peter, while Peter was publicly preaching the Gospel at Rome before some of Caesar’s knights and producing many testimonies about Christ, being begged by them that they should be able to record what was said, wrote the Gospel which is called the Gospel of Mark, from the things said by Peter - just as Luke is recognized as the pen that wrote the Acts of the Apostles and as the translator of the Letter of Paul to the Hebrews (RDCA, RO 166r).
Are there any Catholic traditions of equites (knights of Caesar) working with the Apostle Paul in evangelizing Spain as desired or predicted in Romans 15:22-29?