The itinerant ministers are not mentioned by Clement or Ignatius. The three orders are apostles, prophets, and teachers, as in 1 Corinthians 12:28,29: "And in the church God has appointed first of all apostles, second prophets, third teachers, then workers of miracles, also those having gifts of healing, those able to help others, those with gifts of administration, and those speaking in different kinds of tongues. Are all apostles? Are all prophets? Are all teachers? Do all work miracles?" The Didache places teachers below apostles and prophets, the two orders which Paul makes the foundation of the Church (Ephesians 2:20). The term apostle is applied by Paul not only to the Twelve, but also to himself, to Barnabas, to his kinsmen Andronicus, who had been converted before him, and to a class of preachers of the first rank. There is no instance in the New Testament or in early Christian literature of the existence of an order called apostles later than the Apostolic age. There is no evidence for a 2nd-century order of apostles, which suggests the Didache is earlier, perhaps no later than about 80. Adolf Harnack, on the other hand, gives 131-160, holding that Barnabas and the Didache independently employ a Christianized form of the Jewish Two Ways, while chapter 16 is citing Barnabas. He places Barnabas in 131, and the Didache later than this. Those who date Barnabas under the reign of the Roman emperor Vespasian mostly make the Didache the borrower in chapters 1 - 5 and in 16. Many, with Funk, place Barnabas under the reign of Nerva. The more common view is that which puts the Didache before 100. Bartlet agrees with Ehrhard that 80-90 is the most probable decade. Sabatier, Minasi, Jacquier, and others have preferred a date even before 70. Owen Chadwick wryly dates the Didache to "the period between about 70 and 110. It may be odd there, but it is much odder anywhere else."