Epiphanius of Salamis, in his Panarion, relates the following somewhat shocking story about the Jewish Patriarch Hillel II (320-365):
When Ellel was dying he asked the bishop who then lived near Tiberias for holy baptism, and received it from him in extremis for allegedly medical reasons. For he had sent for him, as though for a doctor, by Josephus [of Tiberias, the highly-placed Jewish convert and source of this story], and he had the room cleared and begged the bishop, “Give me the seal in Christ!” The bishop summoned the servants and ordered water prepared, as though intending to give the patriarch, who was very sick, some treatment for his illness with water. They did what they were told, for they did not know. But pleading indulgence for his modesty the patriarch sent them all out, and was allowed the laver and the holy mysteries.
But I shall resume my description of the reason for the patriarch’s conversion, and also make Josephus’ own reason plain in every detail to those who care to read it, in the words he used to me. “Just as the patriarch was being granted baptism,” he told me, “I peeped in through the cracks in the doors and saw what the bishop was doing to the patriarch—found it out and kept it to myself. For besides,” Josephus said, “the patriarch had a very ample sum of money ready, and he reached out, gave it to the bishop, and said, ‘Offer it for me. It is written that things are bound and loosed on earth through the priests of God, and that these are what will be loosed and bound in heaven.’ When this was over,” he said, “and the doors were opened, the patriarch’s visitors asked him how he felt after his treatment, and he replied, ‘Great!’ He knew what he was talking about!”
Ephiphanius, Panarion 30.4.5-4.7; 6.1-6.4. Translation by Frank Williams (Brill, 1987)
This account appears in a section of the Panarion regarding the Ebionites. While in Tiberias and working with the Patriarch, Josephus ran across some sequestered copies of Ebionite translations of New Testament books into Hebrew, including, of course, the Gospel of Matthew (known as the Gospel “According to the Hebrews”), but also the Gospel of John, and the Acts of the Apostles. It was the reading of these, and the Patriarch’s deathbed conversion, as Josephus related to Epiphanius, that led to Josephus’ own conversion. Josephus was eventually made a count (κομης/comes) by Constantine, a signal honor. He later built churches in both Tiberias and Sepphoris, and perhaps in Capernaum and Nazareth and elsewhere in Galilee, where no previous Gentile-style churches had been established, though there were synagogues of various groups of Jewish Christians still extant (Ebionite, Nazoreans, and others). There is some question as to whether Josephus established Gentile communities in these churches, or whether his buildings were simply in the style of Gentile churches (presumably that of the triple-apsed basilica).
I wonder what we are to make of the account of Patriarch Hillel II’s deathbed conversion to Christianity? Did Josephus misinterpret what he saw? Did he invent it as a supersessionist tale? Or to somehow inflate his importance? Did it, most surprisingly of all, actually happen? Stranger things have happened, but I find that absurd.