Justin Martyr, also known as just Saint Justin (AD 100–165), was an early Christian apologist, and is regarded as the foremost interpreter of the theory of the Logos in the 2nd century. Most of his works are lost, but two apologies and a dialogue did survive. He is considered a saint by the Roman Catholic Church and the Eastern Orthodox Church.

Most of what is known about the life of Justin Martyr comes from his own writings. He was born at Flavia Neapolis (today Nablus) in Palestine into a pagan family, and defined himself as a Gentile. His grandfather, Bacchius, had a Greek name, while his father, Priscus bore a Latin name, which has led to speculations that his ancestors may have settled in Neapolis soon after its establishment or that they may have descended from a Roman 'diplomatic' community that had been sent there. He received a Greek education. He tells us (Dialogue 2-8) that he tried first the school of a Stoic philosopher, who was unable to explain God's being to him. He then attended a Peripatetic philosopher but was put off because the philosopher was too eager for his fee. Then he went to hear a Pythagorean philosopher, who demanded that he first learn music, astronomy and geometry, which he did not wish to do. Subsequently, he adopted Platonism after encountering a Platonist thinker who had recently settled in his city. Some time afterwards, he chanced upon an old man, possibly a Palestinian or Syrian Christian, in the vicinity of the seashore, who engaged him in a dialogue about God, and spoke of the testimony of the prophets as more reliable than the reasoning of philosophers. It was this argument which, Justin avers, kindled in him a love of Christ, and led him to embrace the Christian faith. He was influenced in this by the fearless conduct of the Christians facing execution (Apol. 2:12). His conversion is commonly assumed to have taken place at Ephesus, though it may have occurred anywhere on the road from Palestine to Rome.

The First Apology was an early work of Christian apologetics addressed by Justin Martyr to the Roman Emperor Antoninus Pius. In addition to arguing against the persecution of individuals solely for being Christian, Justin also provides the Emperor with a defense of the philosophy of Christianity and a detailed explanation of contemporary Christian practices and rituals. This work, along with the Second Apology, has been cited as one of the earliest examples of Christian apology, and many scholars attribute this work to creating a new genre of apology out of what was a typical Roman administrative procedure.

Main Article: Justin Martyr

Justin Martyr was born in Flavia Neapolis, a Greek-speaking town within the Roman Empire. In the Dialogue, Justin explains how he came to Christianity after previously passing through the schools of Stoicism, Peripateticism, and Pythagoreanism. After becoming interested in Platonism, Justin eventually converted to Christianity after an encounter with an old man, which Justin describes in the Dialogue as “a love of the prophets, and of those people who are friends of Christ [that] possessed me.” The equating of Christianity with philosophy is important for Justin, as it explains the importance of the Apologies in defending Christianity in philosophical terms.