Barnabas accompanied Paul.
Philippi
This depends on the context. See related questions or re-ask the question.
St. Thomas was the first missionary to preach the Gospel in India and was martyred there for doing so.
Before we can give a factual to your question, first we have to agree what books/epistles did St. Paul write. see related question "What books of the Bible did Paul write" Paul invented Christianity. Jesus was Jewish.
A:Mentioned only in Acts of the Apostles, Saul is the name of the apostle Paul before his conversion and his first missionary journey. Tarsus is also given in Acts as the home town of Saul. In his own epistles, Paul never mentions having been called Saul, or having come from the city of Tarsus. In spite of this, it is certainly possible that he had been called Saul and that he was from Tarsus. However, we can never be certain whether the author of Acts of the Apostles, writing several decades after the death of Paul, was mistaken in those attributions. Some of the key passages regarding Saul in Acts of the Apostles have parallels to a Saulus whom Josephus mentions in Antiquities of the Jews, a book with which the author of Acts is known to have been familiar. Josephus even talked of a riot in Jerusalem, led by Saulus after the stoning of James. Although this Saulus could have inspired the author of Acts, he could not really have been the same person as Paul.
The three places of Pauls journey were Corinth, Antioch and Thesolonica.
Paul's first cohort and companion was Barnabas, who traveled with him on his first missionary journey to Asia Minor. Barnabas played a key role in supporting and encouraging Paul in his ministry, and the two worked closely together in spreading the gospel.
Missionary
Paul's traveling companions changed often. Some of the better-known men who accompanied him from time to time include Barnabas, John Mark, Silas, Luke, and Timothy. In his letters, Paul also mentions lesser-known companions such as Gaius and Aristarchus (Acts 19:29), and Epaphroditus (Philippians 2:25).
I think its in Antioch
Paul's First Missionary Journey. Recorded in Acts 13: 1 to 13
Pauls first mission occurred in A.D. 47. The Book of Acts records this in Acts 13:2-14:28. The earliest of Paul's Epistles, Galations (A.D. 48), 1 and 2 Thess. (A.D. 50), occurred during Paul's second journey.
Many biblical scholars believe that the first missionary journey of Paul of Tarsus was to Cyprus. There is not 100% agreement with this however.
In the book of Acts it is said Paul went on his third missionary journey along with his companion who were his co workers they were young men called Silas and Barnabas.
john
2 years
Paul's first missionary journey was around 46 A.D. And he took along with him his aid, a person called Barnabas.