The Karaite-Zoroastrian theory suggests that Islam began as an alliance between the Karaites and Zoroastrians to fight against [[Marcionism]].
According to the Karaite-Zoroastrian theory the Quranic Isa is Yeshu HaNotzri is , not Jesus but the completely human son of his brother Joses Pantera and Miriam Magdalene who had a brother called Aaron.
