by 
“All Roads Lead To Rome” was a popular saying in the Apostle Paul’s time, probably because the Roman Empire’s roadways radiated outwards from its capital. The city of Rome resided in a space of about or less than ten miles that held around one million people, shocking.
“In Romans 16:22 Tertius “who wrote this letter” greets the readers. Paul is the author of the letter, but Tertius is the scribe or amanuensis who did the actual writing. The name means “third” in Latin and was a common name for slaves (Jewett, 978)” If you want to study this further go to
https://readingacts.com/2016/09/12/who-was-tertius-romans-1622/
The church was already established in Rome when Paul wrote Romans. “the city of Rome was predominately populated by Gentiles and so it is expected that the church was comprised of both Jewish and Gentile believers”. It is believed that there was between 40,000 and 50,000 Jews in the city.
How the church became established in Rome we don’t know. Possible explanations are some were present at Pentecost but also the gospel was being preached in other countries and could have been brought back to Rome.
Paul was staying in Corinth when he wrote the Epistle. His intent was to get offerings from the Gentile Christians for the church in Jerusalem. Paul sent Phoebe of Cenchrea to the church in Rome as the bearer of the epistle. Paul “intended on going to visit the Roman church for a time to preach the Gospel to them. His subsequent plans were then to go westward to preach the gospel in Spain.”
Paul begins Romans 1;7 “To all those in Rome who are loved by God and called to be saints: Grace to you and peace from God our Father and the Lord Jesus Christ.”
“. It also seems that there were multiple churches in the Empire’s capital because there is made mention of an additional church in the home of Priscilla and Aquila (Rom 16:5).” So Paul intended for his letter to be read by all the saints in Rome.
The Epistle was to give the overview of the gospel, not to deal with any specific situations.
“The greatest and most evident theme in the epistle is the subject of the gospel. Paul begins his letter by stating that he was called to be an apostle for the gospel’s sake (1:1). Paul’s dedication belonged to Christ and his gospel as he preached it with his whole heart (1:9). The gospel is also portrayed as the power of God unto salvation-that is able to save those who believe (1:16). This same gospel was not accepted by all the Israelites (10:16), yet graciously (and fortunately) includes the gentiles as well (15:16).
God’s righteousness is being revealed in this gospel from faith to faith (1:17). The only way this righteousness may be accessed is through faith. Sola Fide-it is by faith alone. Man can never make himself righteous, nor will a single ounce of merit do anything in regards to salvation (Eph 2:8, 9). Paul adds to this and says that the one who is righteous by faith shall live (1:17). And this is his gospel which he develops throughout Romans. In this letter Paul shows why it is necessary to be justified by faith. Because of man’s sin, man needs to be justified, and therefore, as a result, (eternal) life will come. Matthew Black rendered it as follows: “‘The just-by-faith (in Christ) shall live (now and for ever)’-and the words, of course, mean enjoy fullness of life, now and fore ever.” [11] It has an eternal consequence-everlasting life: For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord (6:23).”
References;
https://www.google.com/search?q=who+did+paul+write+romans+to&rlz=1C1CHBF_enUS899US899&oq=who&aqs=chrome.0.69i59j69i57j35i39j0l2j69i60j69i61l2.1193j0j7&sourceid=chr
https://www.sparknotes.com/lit/newtestament/section6/
https://www.blueletterbible.org/study/intros/romans.cfm
https://readingacts.com/2016/09/12/who-was-tertius-romans-1622/