Sossianus Hierocles (fl. 303 AD) was a late Roman aristocrat and office-holder. He served as a praeses in Syria under Diocletian at some time in the 290s. He was then made vicarius of some district, perhaps Oriens (the East, including Syria, Palestine, and, at the time, Egypt) until 303, when he was transferred to Bithynia. It is for his anti-Christian activities in Bithynia that he is principally remembered. He was, in the words of the Cambridge Ancient History, "one of the most zealous of persecutors".[1] While in Bithynia, Hierocles authored Lover of Truth (Greek: Φιλαλήθης, Philalethes; also known as Φιλαλήθης λόγος, Philalethes logos), a critique of Christianity. Lover of Truth is noted as the first instance of the trope, popular in later pagan polemic, of comparing the pagan holy man Apollonius of Tyana to Jesus Christ.
Hierocles was among the campaigners for a stronger policy against Christians present at Diocletian's court through the early 4th century. The campaigners' aims were as realized in February 303 with the edicts of the Great Persecution, which expelled Christians from government service, deprived them of normal legal rights, and left them open to imprisonment and execution if they did not comply with traditional religious rites. Hierocles was an avid enforcer of these edicts in his function as praeses of Bithynia, and again while serving as praefectus Aegypti during the late 300s or early 310s. It is largely through incidental notes in the Christian author Lactantius' On the Deaths of the Persecutors and Divine Institutes and Eusebius of Caesarea's On the Martyrs of Palestine and Against Hierocles that we are aware of his activities. Inscriptions at Palmyra preserve the details of his early career.