Jamasp (not to be confused with Djamasp) was an Iranian philosopher in the time of Zarathustra. Djamasp (also transcribed as Jamasp or Zamasp) was a Sassanid king who ruled from 496 - 498. Zoroaster ( Latinized from Greek variants) or Zarathushtra (from Avestan Zaraθuštra) also referred to as Zartosht (زرتشت Jamasp was the Grand Vizier of Gushtasp. For other uses see Hystaspes Vishtaspa (Vištaspa is the Avestan language name of Zoroaster's first patron as primarily described
The book Jamasp Namag is about him. The Jamasp Nameh (var Jāmāsp Nāmag, Jāmāsp Nāmeh, "Story of Jamasp" is a Middle Persian book of revelations
دوستخواه، جلیل: اوستا، کهنترین سرودهای ایرانیان، چاپ دوم، انتشارات مروارید، تهران ۱۳۷۴.