Most of what is known about the life of Justin Martyr comes from his own writings. He was born at Flavia Neapolis (modern Nablus) in Palestine. The city had been founded by Vespasian in the aftermath of the destruction of Jerusalem in AD 70.
Justin suffered martyrdom at Rome under Marcus Aurelius when Rusticus was prefect of the city (between 162 and 168).
He calls himself a Samaritan, but his father and grandfather were probably Greek or Roman, and he was brought up a pagan. It seems that he had property, studied philosophy, converted to Christianity, and devoted the rest of his life to teaching what he considered the true philosophy, still wearing his philosopher's gown to indicate that he had attained to the truth. He probably travelled widely and ultimately settled in Rome as a Christian teacher.