Rom 15:20 Yea, so have I strived to preach the gospel, not where Christ was named, lest I should build upon another man's foundation:
Someone is lying to you...Paul would never have preached in the same town as Peter...Your history is terribly skewed...
In the book of Romans Paul specificly states that "I am ready to preach the gospel to you that are at Rome also" Roman 1:15.