Schaff, Philip. History of the Christian Church (The Complete Eight Volumes in One). Amazon Kindle Edition, 2014.
Volume 2, Ante-Nicene Christianity A.D. 100-325, “Chapter 13. Ecclesiastical Literature of the Ante-Nicene Age, and Biographical Sketches of the Church Fathers.” sec. 159-204.
§ 176. Theophilus of Antioch.
“Theophilus was converted from heathenism by the study of the Scriptures, and occupied the episcopal see at Antioch, the sixth from the Apostles, during the later part of the reign of Marcus Aurelius. He died about A.D. 181” (Schaff 2014, loc. 21781). Schaff says we know him through three books addressed to Autolycus, a friend of his. In contrast to Justin Martyr, who is charitable in his attitude toward the pagan philosphers, Theophilus takes a strongly negative tone, saying that the truth found in Socrates and Plato is stolen from the Old Testament prophets.
Schaff finds Theophilus as the first to use the term “triad” for the Trinity (Schaff 2014, loc. 21791). Theophilus describes Christians as moral and self controlled people.
Theophilus is known to have written additional works, some mentioned by Eusebius, others by Jerome, which we do not currently have (Schaff 2014, loc. 21795). Schaff observes that Jerome disputes the authenticity of the commentaries of Theophilus due to the lack of stle compared to his known work to Autolycus. The Commentary on Matthew was published, based on a manuscript since lost, in 1576 and again in 1883 (Schaff 2014, loc. 21809). Considerable doubt as to the authenticity of the Commentary exists, and was a matter of debate in Schaff’s time, with, among others, Schaff and Harnack engaged in the disputes.