Luke, the writer of the New Testament books the Gospel of Luke, and the Acts of the apostles, was a physician by trade.  From his writings, it is also clear that he was a very learned man. 

Luke first met the apostle Paul at Troas on Paul's second missionary journey.  On Paul's third missionary journey, we find Luke living in Philippi.

It would appear that Doctor Luke was a constant companion of the apostle Paul through his first imprisonment in Rome.  And even during his second imprisonment to some extant.

He was Paul's medical advisor and undoubtedly prolonged Paul's life and rescued him from many a serious illness.  he was a medical missionary.

There are several Church traditions as to his manner and place of death.  One is that he died peacefully in Boeotia and the other is that he was crucified with the apostle Andrew at Patras or at Elaea in Peloponnesus.