History on Ephesus…..according to Christian’s Classics Ethereal Library

• The city of Ephesus, a Grecian city on the Asiatic coast almost exactly east of Athens, was a great commercial metropolis in the first century, and the capital of the Roman province which was called by the name of Asia.
• Its greatest distinction hitherto had been, not its commercial pre-eminence, but the splendid temple of Diana, which was counted one of the Seven Wonders of the world.
• It was written at a time when Paul was a prisoner. Tychicus was the messenger to whom, on the same journey, were entrusted both this (6:21) and the Epistle to Colosse (Col. 4:7).

About Tychicus……According to Russell Kelfe 

• The letter encyclical or “circular” letter, one addressed to one church, but intended to be read in all the churches in Asia. For that to happen, two things must take place. Someone reliable must see that it was delivered to each church, and that someone must be so discerning that he could not only read the letter, but answer questions and respond to inquiries about the Apostle and the issues discussed in the letter.    
• Paul describes Tychicus as “dear brother and faithful servant” in the Lord, who would tell the assigned churches everything. And was always there to do the least important things in the most dependable way.
• His real motivation for sending this particular man was that this particular man could share Paul’s heart as well as Paul’s ministry. He knew the man, and he knew the mission.