Philo of Alexandria (Trinity series)
Philo was a Jewish Theologian that is thought to live just prior to the Christian Era (may have lived to see the beginning of Christianity). He was greatly admired by the Church Fathers and often considered as a kind of an honorary Christian or a Christian Before His Time.
Philo studied Greek Philosophy and used that in his studies of the Old Testament. He believed himself a Mystagogue a person who uncovers mysteries. And he popularized the use of Greek concepts and Terminology. The use of Logos in the book of John for instance may be seen as coming from his influence. He also borrowed the Stoic concept of Trinity for his own Theology which is what Christians would begin to do a century after his death. The web site linked shows some parallels of Philo to various Christian / New Testament Characteristics.
I had a chance to read a little of Philo's "Trinity" a few years back. A bit hard to understand, but I seem to recall it as being kind of similar to how "Oneness Pentecostals" (Sabellian or Monarchians) consider the Trinity to be (Essentially different manifestations or roles of God).
http://trisagionseraph.tripod.com/philo.html
