Jamasp (sage) explained

Jamasp was an Iranian philosopher in the time of Zoroaster.

Jamasp was the Grand Vizier of Gushtasp.

The book Jamasp Namag is about him.

Sources

دوستخواه، جلیل: اوستا، کهن‌ترین سرودهای ایرانیان، چاپ دوم، انتشارات مروارید، تهران ۱۳۷۴.