What did the Roman Christians think when Paul told them he was under obligation to foolish Barbarians?

First, I thank my God through Jesus Christ for all of you, because your faith is proclaimed in all the world. For God is my witness, whom I serve with my spirit in the gospel of his Son, that without ceasing I mention you always in my prayers, asking that somehow by God’s will I may now at last succeed in coming to you. For I long to see you, that I may impart to you some spiritual gift to strengthen you— that is, that we may be mutually encouraged by each other’s faith, both yours and mine. I want you to know, brothers, that I have often intended to come to you (but thus far have been prevented), in order that I may reap some harvest among you as well as among the rest of the Gentiles. I am under obligation both to Greeks and to barbarians, both to the wise and to the foolish. So I am eager to preach the gospel to you also who are in Rome.

This is the reason why I have so often been hindered from coming to you. But now, since I no longer have any room for work in these regions, and since I have longed for many years to come to you, I hope to see you in passing as I go to Spain, and to be helped on my journey there by you, once I have enjoyed your company for a while. At present, however, I am going to Jerusalem bringing aid to the saints. For Macedonia and Achaia have been pleased to make some contribution for the poor among the saints at Jerusalem. For they were pleased to do it, and indeed they owe it to them. For if the Gentiles have come to share in their spiritual blessings, they ought also to be of service to them in material blessings. When therefore I have completed this and have delivered to them what has been collected, I will leave for Spain by way of you. I know that when I come to you I will come in the fullness of the blessing of Christ.

Paul spends much of Romans condemning Jewish boasting in their election and then warning the Roman Christians from committing the same sin against Israel (Romans 11).  But what were Roman attitudes about Spain?