Paul, Silvanus, and Timothy, to the assembly of the Thessalonians in God our Father, and the Lord Jesus Christ:
Paul and Silvanus and Timothy ...  As the Thessalonian church was constituted largely of Gentiles, there had been no contradiction of his apostolic authority; and whatever slanders had been leveled against him had "risen over Paul's character."[1] Paul's true character was of such noble quality that it formed the natural fountain of his moral and religious authority without any appeal to the apostolic office which was rightfully his.  Besides that, "Paul was on such intimate terms with the readers that it was natural to omit it."[2] The title was also omitted in other letters, as from Philippians and Philemon, where the same love and friendship for Paul prevailed.