Note: As a service to fellow researchers, I am going to post critical biographies of the church fathers I examined in my book The Trinitarian Testimony of the Spirit. These biographical overviews were included in my original dissertation but were cut from the published version. Original footnotes are included as endnotes below; in conjunction with the essential bibliographies I have posted, this should help those looking to get into the literature on the early church fathers. I have been struck by how many published sources read the primary sources with a fairly uncritical lens; in these summaries, like any good historian, refuse to take primary sources at face value.
Justin Martyr: A Critical Biography
In his writings, Justin reports some basic facts about his life. At the outset of his 1 Apology, Justin writes that he was born in the Palestinian city of Flavia Neapolis (modern-day Nablus in the northern West Bank). Established during the reign of Vespasian (69–79 CE), this colony town was located in Samaria, near the ancient site of Shechem. Justin also notes in this passage that he is the son of Priscus and the grandson of Bacchius; the latter name is Greek, while the former, like Justin’s own name, is Latin, suggesting Roman descent. In the absence of any more specific evidence, most scholars assign the date of Justin’s birth to the late first or early second century. Elsewhere in his writings, Justin purports to be a Gentile convert to Christianity. Interestingly, despite his birth in Samaritan Palestine, he claims to have been entirely ignorant of Mosiac religion and the Hebrew prophets until late in life.
Justin’s writings also provide a basic sketch of his education and life as a philosopher. In the prologue of his Dialogue with Trypho (chs. 1–9), Justin recounts how he rejected one philosophical school after another until becoming a follower of Platonism. His later decision to instead embrace Christianity as the one true philosophy seems to have come about on account of a chance meeting with an old man who directed him to the Hebrew prophets and thus to Christ. While Justin’s conversion narrative has no doubt been shaped in light of the dramatic and literary conventions of his day, there is no reason to reject the historicity of its basic elements. That Justin continued to see himself as a philosopher even after his conversion to Christianity is evident on account of his distinctive gown.
For the rest of Justin’s biography, we are dependent on sources other than his own writings. In particular, we are forced to depend on Eusebius and his “moving but not wholly reliable” report of Justin’s life. Much of Eusebius’s account simply confirms what Justin already told us about himself, though Eusebius helpfully specifies that Justin was living in Rome and at the height of his activities during the reign of Antoninus Pius (138–161 CE), engaging in both public disputation as well as the informal teaching of pupils, including Tatian, in the model of a philosophical school. Justin’s time in Rome thus overlapped with that of another figure of enormous importance for early Christianity, Marcion of Sinope, who was active in Rome during this same period.
Eusebius suggests that Justin was martyred at the instigation of Crescens, a Cynic philosopher with whom Justin frequently debated. Tatian, Justin’s disciple, merely suggests that Crescens conspired against Justin and himself, and as such Eusebius has likely made a plausible inference about what is otherwise unknown. A longer account of Justin’s trial and martyrdom also survives from antiquity and places the time of Justin’s death during the prefecture of Rusticus (162–168 CE), when Justin was living in Rome for the second time and informally teaching students from his living quarters above the bathhouse of Martinus.
 For a basic overview of Justin’s life, from which this section is drawn, see Henry Chadwick, “Justin Martyr’s Defence of Christianity,” BJRL 4 (1965): 275–78; L. W. Barnard, Justin Martyr: His Life and Thought (London: Cambridge University Press, 1967), 4–13; Osborn, Justin Martyr, 6–10; Craig D. Allert, Revelation, Truth, Canon and Interpretation: Studies in Justin Martyr’s Dialogue with Trypho, VCSup 64 (Leiden: Brill, 2002), 28–31; David Rokéah, Justin Martyr and the Jews, JCP 5 (Leiden: Brill, 2002), 1–2; Denis Minns and Paul Parvis, eds., Justin, Philosopher and Martyr: Apologies, OECT (Oxford: Oxford University Press, 2009), 32–33.
 1 Apol. 1.1 (SC 507:128).
 Osborn, Justin Martyr, 6.
 1 Apol. 1.1 (SC 507:128).
 Allert, Revelation, 28.
 Osborn, Justin Martyr, 6. Barnard (Justin Martyr, 5) speculates that Justin’s ancestors were some of the earliest Roman settlers of Flavia Neapolis.
 Barnard (Justin Martyr, 5) further suggests that the only facts we can know definitively about Justin are that he taught in Rome during the reign of Antoninus Pius and that he was martyred during the reign of Marcus Aurelius; still, he infers that Justin was likely born in the late first or early second century. This conclusion is echoed by Allert, Revelation, 28. Osborn (Justin Martyr, 6) favors a date in the early second century.
 Dial. 41.3 (PTS 47:138). Justin was, therefore, uncircumcised; cf. Dial. 28.2 (PTS 47:115). Osborn (Justin Martyr, 6) notes that Justin does at Dial. 120.6 (PTS 47:278) describe the Samaritans as his people but that he nonetheless never ceased to self-identify as a Gentile. Cf. Minns and Parvis, Justin, 32.
 As seems to be implied in Dial. 7.1 (PTS 47:82); cf. Osborn, Justin Martyr, 6.
 Dial. 2 (PTS 47:71–73); cf. Barnard, Justin Martyr, 6–7.
 Dial. 3–8 (PTS 47:73–85). Allert (Revelation, 29) notes that Justin gives the witness of the martyrs as a second reason for his conversion to Christianity in 2 Apol. 12.1 (SC 507:356). Barnard (Justin Martyr, 13) suggests that Justin’s conversion from Platonism to Christianity likely took place shortly before the outbreak of the Bar Kochba revolt (ca. 132 CE).
 For instance, though Erwin R. Goodenough, The Theology of Justin Martyr (Jena: Frommannsche Buchhandlung, 1923; repr., Amsterdam: Philo Press, 1968), 58–59 sees Justin’s conversion account as merely following literary convention, Barnard (Justin Martyr, 11) and Osborn (Justin Martyr, 7–8) believe Justin’s story to be rooted in history.
 Cf. Dial. 1.2 (PTS 47:69), in which Trypho identifies Justin as a philosopher on account of his attire.
 Osborn, Justin Martyr, 8.
 Allert, Revelation, 29; cf. Hist. eccl. 4.8 (SC 31:170).
 Hist. eccl. 4.11 (SC 31:175–76). On Justin’s “school,” see further Barnard, Justin Martyr, 12–13; Osborn, Justin Martyr, 8–9; Harlow Gregory Snyder, “‘Above the Bath of Myrtinus’: Justin Martyr’s ‘School’ in the City of Rome,” HTR 100 (2007): 335–62; Jörg Ulrich, “What Do We Know about Justin’s ‘School’ in Rome?” ZAC 16 (2012): 62–74; Tobias Georges, “Justin’s School in Rome—Reflections on Early Christian ‘Schools,’” ZAC 16 (2012): 75–87. For more on the extent and nature of Christianity in Rome in and around Justin’s time, see Peter Lampe, From Paul to Valentinus: Christians at Rome in the First Two Centuries, ed. Marshall D. Johnson, trans. Michael Steinhauser (Minneapolis: Fortress, 2003), and especially 257–84 on Justin.
 Justin mentions Marcion and his followers by name at 1 Apol. 26.5, 58.1 (SC 507:200, 281); Dial. 35.6 (PTS 47:129). Regarding Marcion’s chronology, the traditional view, following patristic sources, is that Marcion arrived in Rome ca. 140 CE, was expelled from the community of the orthodox Roman churches and founded his own in July of 144, and died around 160; see further Lampe, From Paul to Valentinus, 241–56, who follows the work of Adolf Harnack, Marcion: Das Evangelium vom Fremden Gott (Leipzig: Hinrichs, 1921). R. Joseph Hoffmann, Marcion: On the Restitution of Christianity: An Essay on the Development of Radical Paulinist Theology in the Second Century, AARAS 46 (Chico, CA: Scholars Press, 1984), 74, presents an alternative chronology that is far more skeptical of the early sources, suggesting that Marcion was active in Asia Minor ca. 110–150 CE and that his purported trip to Rome was a patristic fiction. Hoffmann’s work has not been well-received; cf. the criticisms of Sebastian Moll, The Arch-Heretic Marcion, WUNT 250 (Tübingen: Mohr Siebeck, 2010), 7–8. In the most recent work on Marcion, Judith M. Lieu, Marcion and the Making of a Heretic: God and Scripture in the Second Century (Cambridge: Cambridge University Press, 2015), 297, accepts “the most stable tradition that associates Marcion with Rome.” A vigorous defense of the traditional chronology and Marcion’s activity in Rome may be found in Moll, Arch-Heretic Marcion, 25–46.
 Hist. eccl. 4.16 (SC 31:190–92).
 Or. Graec. 19.2 (PTS 43:39).
 Osborn, Justin Martyr, 9; contra Barnard, Justin Martyr, 5–6.
 Adalbert G. Hamman, “Essai de chronologie de la vie et des oeuvres de Justin,” Aug 35 (1995): 231–39, places Justin in Rome from roughly 140–150 CE and 155–165 CE, with an intervening stay in Palestine. Allert (Revelation, 30) suggests that Justin was more of an itinerant teacher headquartered in Rome than he was the leader of a permanent school. Cf. Barnard, Justin Martyr, 12.
 The text and translation of the Acta Justini can be found in Herbert Musurillo, ed. and trans., The Acts of the Christian Martyrs (Oxford: Oxford University Press, 1972), 42–61. Osborn (Justin Martyr, 8) notes that this account seems authentic, lacking later “credulous ornamentation.” This form of the tradition likely comes from the third century (Barnard, Justin Martyr, 6), though its roots no doubt go back into the second. For more details on Justin’s location in Rome, see Minns and Parvis, Justin, 57–59. On the date of Justin’s death, scholars find the year 165 CE to be the most plausible; cf. Minns and Parvis, Justin, 32; Barnard, Justin Martyr, 5.