Jethro יתרו
a Midianite priest, Moshe's father-in-law, an early convert
Yitro was a priest of Midian — by midrash he had tried every cult in the world before concluding they were empty, and was driven out of his town for it, which is why his daughters were kept from the well. There a fugitive from Egypt defended them, and Yitro took him in.
For forty years Moshe herded his flocks. When Moshe returned at the head of a nation, Yitro came to him in the wilderness with Tzipporah and their sons, heard the story of the plagues and the sea, and said: «Now I know that the Lord is greater than all gods.» The sages debate whether he arrived before or after the giving of the Torah, but agree that he became a convert.
His contribution was practical. Seeing Moshe judging alone from morning to night, he said plainly: «What you are doing is not good; you will wear yourself and the people out» — and proposed chiefs of thousands, hundreds, fifties and tens, with only the hardest cases reaching Moshe. Moshe accepted, and the Torah portion bears Yitro's name.