Over at Unsettled Christianity, Joel Watts has a post about Justin Martyr and his references to the Gospels as “memoirs of the apostles,” in relation to Xenophon’s Memorabilia.
I’ve been working on this topic in my own research of late, and here’ what I’ve surmized.
Justin was acquainted with the Socratic tradition. He explicitly cites Plato and Xenophon, and he could well have known Xenophon’s Memoirs of Socrates and Plato’s “Socratic Dialogues” as they were highly esteemed among the philosophers that he debated with. Hardly unexpected given that many biographies were disseminated widely, not just in the Socratic tradition, but Pythagorean memoirs too, as circulated by the prominent historian Alexander Polyhistor in the middle of the first century in Rome. The philosopher Favorinus of Arelate (d. ca. 160), friend to Emperor Antoninus Pius, published his own “memoirs” around the same time that Justin was in Rome. By using the term apomnemoneumata, Justin is the first, as far as we can tell, to liken the Gospels to the biographical tradition. His attempt to approximate the Gospels to another known literary genre is without doubt our best clue to what type of literature that the Gospels were received as by their early readers. That is not to say that the Gospels are exactly modeled on any particular type of the biographical tradition, but the Gospels belonged to the same literary family. I suggest that Justin’s equating the Gospels with the biographical memoirs of great philosophers is an apologetic ploy, designed to show that Christianity was a genuine philosophy, and that Christian accounts of Jesus contained cultural sophistication, but without sophistry.
 Cf. Justin, 2 Apol. 10.5 (Plato’s Apology for Socrates); 10.8 (Socrates had some knowledge of Christ); 11.2-3 (Xenophon’s story of Herakles at the crossroads).
 Koester (Ancient Christian Gospels, 38-39) points out that the Latin designation for Xenophon’s biography of Socrates as Memorabilia,was not used until Johann Lenklau’s 1569 edition of Xenophon. Even so, the Greek title for the work, “First Book of Xenophon’s Memoirs of Socrates” was extant in some manuscripts and such a title, or a source like it, is probably what influenced Justin.
 David L. Dungan, A History of the Synoptic Problem: The Canon, the Text, the Composition, and the Interpretation of the Gospels (ABRL; New York: Doubleday, 1999), 31-32.
 Koester (Ancient Christian Gospels, 37-40) is of the opinion that Justin regarded the written Gospels as a more reliable account of Jesus’ words and deeds than extant oral traditions about Jesus. Indeed, in Koester’s perception, Justin sought to “replace” the oral Gospel with the written Gospels. Several problems count against that proposal: (1) Justin nowhere delineates a distinction between oral and written accounts of Jesus, so any attempt to regarded him as implicitly supplanting a continuing oral tradition with written texts is a category mistake. Justin does not even appear to differentiate authorized and unauthorized accounts of Jesus, and cites “other” Jesus traditions in isolated instances (see Dial. Tryph. 47.5; 78.5; 88.3). Justin argues, in fact, that the traditions of sayings and deeds of Jesus found in the “memoirs” are based on what Christ taught and transmitted to his followers (1 Apol. 4.7; 6.2; 8.3; 65.5; 66.1-3 [note the repeated use of paradidomi for "handing over" traditions); (2) Justin appears to know the Papian tradition of Mark's association with Peter in composing his Gospel and yet speak no ill of the tradents of the tradition (Dial. Tryph. 106.3); (3) Koester does not think that Justin's designation of the Gospels as "memoirs" was influenced by the Graeco-Roman biographical tradition, but derives instead from a view of the Gospels as based on ancient memory, as in Papias. In which case, it is surely odd that Justin is somehow critical of oral tradition, while using a key term from oral tradition, i.e., "memory," to designate the Gospels; and (4) Thus Koester's view is truly peculiar that Justin coined the term "memoirs" from Papias, but with a view to eclipsing the "living voice" esteemed by Papias, and likewise strange is the claim that Justin made appeals to "remembering" with an anti-Gnostic intention, perhaps aware of similar appeals to remembering in Apoc. Jas. 2.1-15, but Justin was unlikely to be unaware of the use "memoirs" by the Second Sophist. Would Justin have been more likely to have encountered the Apocryphon of James than Xenophon's biography of Socrates? It is far more likely that Justin's use of "memoirs" was influenced by both the general tradition, known also to Papias, that the Gospels were based on apostolic memory, and also by the Socratic biographical tradition (so also Dungan, History of the Synoptic Problem, 33; Hengel, Four Gospels and the One Gospel of Jesus Christ, 212 n. 13).
 Note the words of Martin Hengel (Acts and the History of Earliest Christianity [Philadelphia: Fortress, 1980], 29): “The ancient reader will probably have been well aware of the differences in style and education, say, between Mark and Xenophon; but he will also have noticed what the gospels had in common with the literature of biographical ‘reminiscences’ ‒ and unlike the majority of German New Testament scholars today, he did not mind at all regarding the evangelists as authors of biographical reminiscences of Jesus which went back to the disciples of Jesus themselves.”
 Justin calls Christianity “philosophy safe and simple” (Dial. Tryph. 8.1), he extols Christians as those “who have lived in accordance with the Divine Reason” (1 Apol. 46), and regards Jesus as a great philosophical teacher by drawing attention to the brevity rather than bombastic nature of Jesus’ teaching (Dial. Tryph. 18.1; 1 Apol. 14.4). See Stanton, Jesus and Gospel, 103-5; Dungan, History of the Synoptic Problem, 32.